Question

the ratio of john collection of baseball cards to billy's collection is 8:5. if John has 100 cards, how many does billy have?

Answer 1

Let x be the number of cards Billy have

8 : 5 = 100 : x

$\frac{8}{5}=\frac{100}{x}$

cross-multiply

8x = 500

Divide both-side of the equation by 8

x= 62.5

x ≈ 63