To make strong coffee, 3 scoops of coffee beans make 15 cups. To make weak coffee, the amount of beans used should be 5/8 the amount used for strong coffee.

Question

About how many scoops should be used to make 30 cups of medium coffee?

A) 2

B) 3

C) 5

D) 6

Answer 1

You'd need 6 scoops to make 30 cups of strong coffee. To make 30 cups of weak coffee, you'd need (5/8)(6) = 30/8 ≈ 4 scoops.

2 scoops < 4 and so is 3 scoops. 6 scoops makes us strong coffee, so the answer is C.

Answer 2

Hi. If it takes 3 scoops to make 15 cups, then by the same ratio, it would take 1 scoop to make 5 cups for strong coffee.

Since for weak coffee it takes 5/8 as much beans, then we can say you need 5/8 of a scoop to make 5 cups of weak coffee.

For medium coffee, the number of scoops should be almost exactly

between 5/8 and 1. If we change 5/8 to 10/16 (equivalent fractions)

and convert 1 to 16/16 (equivalent fractions), the middle point would be 13/16 scoops for medium coffee.

We know that 30 cups is 6 times as much as 5 cups. Therefore, if you multiply 13/16 by 6 you get 78/16 cups. 78/16 is close to 5. Therefore, the answer is C, 5.