Evaluate subsequent proportion:

Example 2:

If 5 pounds of apples cost 80 cents, how much will 7 pounds cost?

Solution:

By using x for the cost of 7 pounds of apples, the subsequent proportion can be written.

5 pounds/7 pounds = 80 cents/ x

The product of the extremes is (5)(x) = 5x.

The product of the means is (7)(80) = 560.

Equate these two products which solve the resulting equation.

5x  = 560

5x/5 = 560/5

x = 112

The unit of x is cents.  Therefore, 7 pounds of apples cost 112 cents or $1.12.