She wants to purchase shoes that cost $ 50 she wants to purchase socks that cost 2.20 each......so the expression for this is 2.20s...with s being the number of pairs of socks bought and she only has $ 64....so she has to spend 64 or less...< = 64
so ur inequality would be : 50 + 2.20s < = 64.....subtract 50 from both sides 2.20s < = 64 - 50 2.20s < = 14...divide both sides by 2.20 s < = 14 / 2.20 s < = 6.36....so she can purchase 6 pairs of socks without going over