MAKE AND BUY

In chapter 9 eg 3 on make and buy decisions.

Since the variable cost of making the product is less than purchasing them from outside we would see the saving cost of making them internally on a per kg basis to see how much cost we saved per kg by making them.

Products—————————X——-Y——–Z
Variable cost to make———10——12——14
Buy-in price———————-13——17——16
saving cost by making———3——–5——–2
kilo per unit———————–3——–2——–1
saving cost by kg————–$1—–$2.5——$2
Ranking—————————3——–1———2

However, if the variable cost of making the product is more than purchasing them from outside we would see the saving cost of purchasing from outside on a per kg basis to see how much cost we saved per kg by purchasing them.

Products—————————X——-Y——–Z
Variable cost to make———20——18——15
Buy-in price———————-15——10——-9
saving cost by purchase——5——–8——–6
kilo per unit———————–2——–3——–1
saving cost by kg————-$2.5—-$2.6—–$6
Ranking—————————3——–2———1

Is that correct? we can do it both ways depending which way we save more cost?