I’ve got a question. The Ex.1 says: “Inventory holding costs amount to 10% p.a. of inventory value.” But inventory value’s defined by the price of the desk, which is $25, isn’t it? so, I assume we can’t say that holding of 1 unit is equal to $2.5, because it includes several decks, for ex. in case of 500 units it’s 40,000 / 500 = 80 (desks per unit), and then holding 1 unit of 80 desks will cost us $200. And so on. Where is my mistake, plzzz?
I mean, therefore, the holding of 1 unit of 80 desks will cost us 80 * 2.5 = $200. And on average we are being charged on 250 units for the whole year, so it’ll be 250 * 200 = $50,000. In case of 750 units we’ve got 40,000 / 750 = 53.(3) (desks per unit), therefore 53.(3) * 2.5 = $133.(3) per unit, and (750 / 2) * 133.(3) = $50,000 (total payment for holding). I mean, it should be the same in any case, because the number of desks and the price of 1 desk are constant in the task.
Hi. First of all thanks a million for these free videos. I have question regarding option a. If you order 500 units and they charge you 10% p.a of inventory value in a day-to-day basis. So you pay 625$. I understand that after you sell those units, you will order another “batch” of 500 units. So shouldn’t 625$ be charged again and again (for 80 times) by the storehouse?
Because it is being charged on a day-to-day basis, some days you will be charged on a full 500 units and some days on zero units (because the inventory level keeps going between 500 (when you receive an order) and 0 (just before you receive the next order). So it is as though on average you are being charged on 250 units for the whole year.
Thank you for presenting the lectures. I have a question about the calculations of inventory cost in example 1 part 2 where the order quantities are 750 units. When calculating the reorder cost, it seems not quite realistic to use 53.33 times 20 because the real number or orders should be 54. It is true to use 53.33 if the system is in long run, but here it is just for one-year base. And in terms of the calculations of holding costs, the average inventory level for the last “period” should be 250/2=125. Therefore, I think the calculations for the reorder cost should be 54*20=1080, the inventory cost should be ((750/2)*(53/54)+(250/2)*(1/54))*2.5=926 assuming that the interval between each replenishment is the same, or(((750*3/2)/3)*(159/160)+(250/2)*(1/160))*2.5=933.6 assuming that the items are sold at the same rate.
Could you please correct my faults in this. Thank you
Because the level of inventory keeps moving between the order quantity (when an order has just been received) and zero (just before the next order is received).
So the average inventory throughout the year is the order quantity / 2.
Suppose that the order quantity is 500 each time. You get a deliver of 500, so you have 500 in your warehouse. You sell these 500 over a few weeks/months, and the level of inventory in the warehouse falls to zero. Then you get a new delivery of 500 and the level goes back up to 500. This keeps repeating, so throughout the year the inventory level keeps moving between 500 and zero. Therefore on average the level is (500 + 0)/2 = 250 units.
Have a look at the lecture again – I draw a little graph to illustrate how the inventory level keeps changing and therefore why the average inventory is the order quantity divided by two.
Please do not ask a question about labour under a lecture on inventory control! Ask in the F2 Ask the Tutor Forum.
‘Time and a quarter’ means that for every hour they work they are paid for 1.25 hours. So…..if overtime is 26 hours they will be paid 26 x 1.25 x $4 for the overtime.
Direct cost of labour is basic pay, plus overtime premium on specific job. (Rest is indirect cost)
am unable to see any of the lecture videos, even after refreshing many times and following the support instruction. i didnt face these problems in last december revision time, did open tuition change anything in the format of the videos since last december?
yes i did, but it didnt help, i’ve been trying to open the videos in the past few days and on different computers with different internet connexions but still, a blank page with ads comes up only.
i have a problem with connectivity.When i play these lectures they would do fine upto around 5 mins and its starts to freeze in intervals of 2 then 5 upto 20 seconds at times and would deteriorate until it does not play at all.what can i do to rectify this problem
You can include it, but only if asked for. It is not relevant for the decision because it is the same over the year regardless of how many are ordered each time.
However, the one time when it has to be considered is when there are quantity discounts (see the next lecture).
Thank you for the opentuition initiative. Overall it is outstanding. I just have one comment regarding this section. The average assumption used is too simple. This number should either be given, or additional information provided to calculate it. eg: In the example, the 500 unit average is given as 250, by simply dividing 500 by 2. If stock levels are being ordered every 4.5 days, one would assume the average sales per day to be around 111. This would make the average stock level closer to 333 for the year (try it out with ta simple excel table). By over simplifying examples in the material, a problem could be created in the exam and time could be wasted by the students trying to get their heads around the disconnect.
If 500 units are ordered each time, then the inventory levels vary between 500 and zero and the average inventory is 250 units. The days between orders will be 365 / number of orders, and the number of orders will be the demand per year / the order quantity. It will not be a random 4.5 days!
The EOQ formula itself depends on the assumption that the average inventory level is the order quantity divided by 2 (try proving it yourself, even if though the proof is not in the syllabus).
We do not over simplify the examples and a problem cannot be created in the exam as a result. To say that time could be wasted by students trying to get their heads round the disconnect is quite simply rubbish – there is no disconnect.
(I know that in a hurry I wrote 4000 instead of 40000, but it should have been obvious that it was meant to be 40000 for the same reason that it was 40000 for each of the other 4 calculations!)
this is the best study material i have seen. so sad im just discovering open tuition.. after wasting so much money on lsbf and still didnt pass.thanks so much
Victoria says
Dear Mr Moffat
I’ve got a question. The Ex.1 says: “Inventory holding costs amount to 10% p.a. of inventory value.” But inventory value’s defined by the price of the desk, which is $25, isn’t it? so, I assume we can’t say that holding of 1 unit is equal to $2.5, because it includes several decks, for ex. in case of 500 units it’s 40,000 / 500 = 80 (desks per unit), and then holding 1 unit of 80 desks will cost us $200. And so on. Where is my mistake, plzzz?
Victoria says
I mean, therefore, the holding of 1 unit of 80 desks will cost us 80 * 2.5 = $200. And on average we are being charged on 250 units for the whole year, so it’ll be 250 * 200 = $50,000.
In case of 750 units we’ve got 40,000 / 750 = 53.(3) (desks per unit), therefore 53.(3) * 2.5 = $133.(3) per unit, and (750 / 2) * 133.(3) = $50,000 (total payment for holding). I mean, it should be the same in any case, because the number of desks and the price of 1 desk are constant in the task.
Regards,
Victoria
Victoria says
OK, never mind, I see it now 🙂
1 unit = 1 desk 🙂
John Moffat says
Thats correct 🙂
(Sorry i did not answer earlier, but your question appeared during the night here and I was asleep 🙂 )
Munazza says
I study the topic before while was doing my B.Com…In Cost Accounting. But this is the best explanation..
Thanks
Bartek says
this is great, many thanks!
Adedayo says
Thanks to the management of Open Tuition!
John Moffat says
You are very welcome 🙂
Al-amin aye says
Lot of thanks for open tuition
tehreem says
OMG. Thank you OT. Now i can watch these lectures on my phone as well!
Martynas says
Hi. First of all thanks a million for these free videos.
I have question regarding option a. If you order 500 units and they charge you 10% p.a of inventory value in a day-to-day basis. So you pay 625$. I understand that after you sell those units, you will order another “batch” of 500 units. So shouldn’t 625$ be charged again and again (for 80 times) by the storehouse?
John Moffat says
Because it is being charged on a day-to-day basis, some days you will be charged on a full 500 units and some days on zero units (because the inventory level keeps going between 500 (when you receive an order) and 0 (just before you receive the next order). So it is as though on average you are being charged on 250 units for the whole year.
Eddie says
Thank you for presenting the lectures. I have a question about the calculations of inventory cost in example 1 part 2 where the order quantities are 750 units. When calculating the reorder cost, it seems not quite realistic to use 53.33 times 20 because the real number or orders should be 54. It is true to use 53.33 if the system is in long run, but here it is just for one-year base. And in terms of the calculations of holding costs, the average inventory level for the last “period” should be 250/2=125. Therefore, I think the calculations for the reorder cost should be 54*20=1080, the inventory cost should be ((750/2)*(53/54)+(250/2)*(1/54))*2.5=926 assuming that the interval between each replenishment is the same, or(((750*3/2)/3)*(159/160)+(250/2)*(1/160))*2.5=933.6 assuming that the items are sold at the same rate.
Could you please correct my faults in this. Thank you
John Moffat says
Why do you say it is just for one year?
The question says there is a demand of 40,000 desks per year – this implies every year.
As I explain in the lecture, some years there will be 54 orders and some years only 53 orders. However there will be 53.33 orders a year on average.
We always make this assumption (and it is important in the exam not to round it).
Without this assumption, the EOQ formula itself is not valid.
Eddie says
oic, but if it is specifically for one year, am I right in the calculations?
John Moffat says
Yes, but it will never ever be for just one year in the exam.
Dipty says
Hi. For holding cost, why do we always have to divide the total number of units by 2? I missed that bit. Thanks
John Moffat says
Because the level of inventory keeps moving between the order quantity (when an order has just been received) and zero (just before the next order is received).
So the average inventory throughout the year is the order quantity / 2.
Dipty says
Sorry I still cant understand this. Do u mean because there are 2 choices? that is why it is divided by 2? :s
John Moffat says
No – there are not two choices.
Suppose that the order quantity is 500 each time. You get a deliver of 500, so you have 500 in your warehouse. You sell these 500 over a few weeks/months, and the level of inventory in the warehouse falls to zero. Then you get a new delivery of 500 and the level goes back up to 500. This keeps repeating, so throughout the year the inventory level keeps moving between 500 and zero.
Therefore on average the level is (500 + 0)/2 = 250 units.
Have a look at the lecture again – I draw a little graph to illustrate how the inventory level keeps changing and therefore why the average inventory is the order quantity divided by two.
kimrong says
Hi John
I have a problem with a phrase:
Overtime is paid at a rate of time and a quarter.
what does it mean? if the workers are paid $4 per hour.
and total overtime 26 hrs, which is 8 hrs for specific order and the rest is general order.
question asking to compute the direct cost of specific overtime.
May u help about it?
John Moffat says
Please do not ask a question about labour under a lecture on inventory control! Ask in the F2 Ask the Tutor Forum.
‘Time and a quarter’ means that for every hour they work they are paid for 1.25 hours.
So…..if overtime is 26 hours they will be paid 26 x 1.25 x $4 for the overtime.
Direct cost of labour is basic pay, plus overtime premium on specific job. (Rest is indirect cost)
magdeline says
Thanks, u completly solved my problem.very easy o understand as compered to text books recommended.
sisnem says
Same here,I MISS THE LECTURES
John Moffat says
The lecture is working find, the problem must be at your end.
Have you looked at the support page (the link is above)?
houyam says
Hi,
am unable to see any of the lecture videos, even after refreshing many times and following the support instruction.
i didnt face these problems in last december revision time, did open tuition change anything in the format of the videos since last december?
John Moffat says
Have you looked at the technical support page? The link to it is above.
houyam says
yes i did, but it didnt help, i’ve been trying to open the videos in the past few days and on different computers with different internet connexions but still, a blank page with ads comes up only.
simbamasara says
i have a problem with connectivity.When i play these lectures they would do fine upto around 5 mins and its starts to freeze in intervals of 2 then 5 upto 20 seconds at times and would deteriorate until it does not play at all.what can i do to rectify this problem
John Moffat says
Have you looked at the technical support page? The link is above.
jameela hinds says
How come the purchase cost is not included in the total cost?
John Moffat says
You can include it, but only if asked for. It is not relevant for the decision because it is the same over the year regardless of how many are ordered each time.
However, the one time when it has to be considered is when there are quantity discounts (see the next lecture).
Grant says
Thank you for the opentuition initiative. Overall it is outstanding. I just have one comment regarding this section. The average assumption used is too simple. This number should either be given, or additional information provided to calculate it. eg: In the example, the 500 unit average is given as 250, by simply dividing 500 by 2. If stock levels are being ordered every 4.5 days, one would assume the average sales per day to be around 111. This would make the average stock level closer to 333 for the year (try it out with ta simple excel table). By over simplifying examples in the material, a problem could be created in the exam and time could be wasted by the students trying to get their heads around the disconnect.
John Moffat says
I am sorry, but you are completely wrong!!!
If 500 units are ordered each time, then the inventory levels vary between 500 and zero and the average inventory is 250 units. The days between orders will be 365 / number of orders, and the number of orders will be the demand per year / the order quantity. It will not be a random 4.5 days!
The EOQ formula itself depends on the assumption that the average inventory level is the order quantity divided by 2 (try proving it yourself, even if though the proof is not in the syllabus).
We do not over simplify the examples and a problem cannot be created in the exam as a result. To say that time could be wasted by students trying to get their heads round the disconnect is quite simply rubbish – there is no disconnect.
Yousaf says
very useful….. thanks
saqibsheeraz says
Great Lecture …)
jawad says
(4000/1250*20=64
wile the tutor show 640
John Moffat says
The demand is 40,000!!!
So it is 40000/1250*20 which is equal to $640!!
(I know that in a hurry I wrote 4000 instead of 40000, but it should have been obvious that it was meant to be 40000 for the same reason that it was 40000 for each of the other 4 calculations!)
munaf says
can not watch the video it says server not found
savitaleo86 says
this is the best study material i have seen. so sad im just discovering open tuition.. after wasting so much money on lsbf and still didnt pass.thanks so much