Final answer:
To determine the amount of peaches needed to make one cup of ice cream, a proportion is used. The calculation reveals that Justin will need 5/9 pound of peaches to make one cup of homemade ice cream.
Step-by-step explanation:
To figure out how many pounds of peaches Justin will need to make one cup of homemade ice cream, we will set up a proportion. Justin uses 1/4 pound of peaches for 9/20 cup of ice cream. The question is, how many pounds for 1 cup.
Let x represent the number of pounds needed for 1 cup. Our proportion is:
(1/4 pound) / (9/20 cup) = x / (1 cup)
To solve for x, cross-multiply and then divide:
(1/4) * (1) = x * (9/20)
Subsequently, we multiply both sides of the equation by the reciprocal of (9/20) to isolate x:
x = (1/4) * (1) * (20/9)
This simplifies to:
x = (5/9) pounds
Therefore, Justin will need 5/9 pound of peaches to make one cup of homemade ice cream.