Jane sells socks at £3 a pair plus £5 for postage of any amount. Jack sells a pair of socks at 1/3 more expensive than Jane but his postage is free.

Question

Maths made easy

Answer 1

1/3 more than 3 = 3+1 = 4 = Jack's selling price

cost = 4S = 3S + 5

4S - 3S = 5

S = 5 socks sold makes Jane and Jack's prices equal = 20

buy more than 5 socks and Jane's cost is cheaper

buy less than 5 socks and Jack's cost is cheaper