A candy costs 20 cents and a packet of 12 similar candies costs $1.00

Question

A candy costs 20 cents and a packet of 12 similar candies costs $1.00. Lily wanted to buy exactly 40 candies. What is the minimum amount that lily spent?

Please tell me the final answer.

Answer 1

buy as many as possible at the lower price

3(12) = 36

buy 3 packs of 12 for $3.00

 

Then she needs 4 more candies 

so 4($0.20) = $0.80

 

$3.80