To solve this problem, we are going to use a proportion, letting the variable x represent the unknown number of cups of oatmeal that we need.
1.5 cups/36 cookies = x cups/60 cookies
To simplify a proportion like this, we can use cross-multiplication. This means multiplying the numerator of one fraction by the denominator of the other fraction and setting it equal to the product of the other numerator and denominator. This is modeled below:
(36)(x) = (1.5)(60)
To simplify, we begin by multiplying out each side.
36x = 90
Finally, we divide both sides of the equation by 36.
x = 2.5
This means that we need 2.5 cups of oatmeal to make the cookies.
Hope this helps!