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PMf5 exam bank

CChris11y ago
Hi John Sorry for this but just sat one the exam bank questions and really struggled to find answer. Question is - sales price is $200. Demand at this price is 100,000 units. Demand will change by 10,000 for every $30 movement on price and variable costs are $8 per unit. My solution (incorrect as not even an option to answer was: P = a - bq means p = 500 - 0.003q MR = a - 2bq means 192 (being 200-8) = 500 - 0.006q; therefore 500-192 = 0.006q means q = 51333 Back to original equations P = 500-0.003x51333 P = 500 - 154. P = 346. The correct answer is $254 and I just can't fathom how to get there. Your help would be much appreciated. Kind Regards Chris
John MoffatJohn MoffatTutor11y ago#1
Hi Chris You started correctly, but then you went wrong :-) P = 500 - 0.003Q That is correct Therefore MR = 500 - 0.006Q MC = 8 (the variable cost per unit) So for maximum profit, MR = MC 500 - 0.006Q = 8 0.006Q = 500 - 8 = 492 So Q = 492/0.006 = 82,000 If you now put Q = 82,000 in the original price/demand equation, you will get P to be $254 I hope that all makes sense :-)
CChris11y ago#2
It does - I'm an idiot! So close yet so far! I was using the MR as $192 rather than $8 as the MC. Silly boy! Getting my MR's and contributions mixed up and ignoring the more obvious (and correct!) figures. Lesson learned and better now than in 2 months time!
CChris11y ago#3
PS - many thanks as always for your prompt response and assistance and clarity. Goes without saying that your support is invaluable (but I'll say it anyway!).
John MoffatJohn MoffatTutor11y ago#4
Thanks Chris :-)
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