With temperatures rising Emma has been stocking up on her favourite ice lollies!
Ice lollies are on offer at three different shops.
The normal price of an ice lolly is the same at each shop.
Shop A – Buy 1 ice lolly and get 2 more ice lollies at half price.
Shop B – Buy 2 ice lollies and get 3 more ice lollies at half price.
Shop C – 30% off ice lollies.
What is the cheapest way for Emma to buy 8 ice lollies?
You can buy from more than one shop.
Answer:
Let L = normal price of ice lolly
Shop A
Cost of each lolly on offer = (L + 0.5L + 0.5L)/ 3 = 2/3 L = 0.667 L
Shop B
Cost of each lolly on offer = (2L + 3 x 0.5L) / 5 = 7/2 x 1/5 = 7/10 L = 0.7L
Shop C
Cost of each lolly on offer = 0.7L
So shop A is the cheapest however you can only buy in multiples of 3 and Emma only wants 8.
So Emma should buy 6 lollies from shop A and then 2 lollies from shop C (shop B’s offer is no good as you have to buy 5 lollies at a time).