Question 1 For what value of r is the equation 8 / 12 = 10 / r true?

-- Answer -- 15

8 * r = 10 * 12 => r = 15

Question 2 A cookie recipe that yields 24 cookies requires 1 3/4 C butter. When the ingredients are increased proportionally, how many cups of butter are required to yield 72 cookies?

-- Answer -- 5.25

1 ¾ / 24 = x / 72 => x = 5.25