Your mother gave you 13.32 with which to buy a present this covered 3/5 of the cost. how much did the present cost?

This a proportion. The 13.32 is 3/5 the cost so what you'd write first is

13.32=3

x 5. Now solve by first multiplying 13.32 by 5 and you get 66.6, and 3 times x. Now you have 66.6=3x. Now divide everything by 3 and you'll get x=22.2. The total is $22.20

13.32 = 3/5

1/5 = 13.32 / 3

1/5 = 4.44

Full cost = 4.44 * 5

= 22.20