Question

Justin bought some yarn from his favorite craft store. He can make one scarf with 35 of a ball of yarn. If he purchases 15 balls of yarn, how many scarves can he make?

Answer 1

Justin can make 42 scarves with 15 balls of yarn

Explanation:

Proportional Quantities

One quantity X is proportional to other Y if X can always be computed by multiplying or dividing Y by any constant number. Percentage calculations always make use of proportions, like when computing 35% of 20 = 35*20/100 = 7. If the quantity was doubled (40), the percentage would have resulted in the double also (14).

Note: We assumed the proportion to be 35%, the percentage sign is missing.

The question explains Justin can make one scarf with 35% (0.35) of a ball of yarn. It means that each ball can produce 1/0.35 scarves. If he purchased 15 balls of yarn, he can produce 15/.35 = 42.9 scarves. We need to round down and say Justin can make 42 scarves with 15 balls of yarn.