Algebra
LINEAR EQUATIONS
Example 2:
If 5 pounds of apples cost 80 cents, how much will 7 pounds cost?
Solution:
Using x for the cost of 7 pounds of apples, the following 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 and solve the resulting equation.
5x = 560
5x
5
560
5
x = 112
The unit of x is cents. Thus, 7 pounds of apples cost 112 cents or
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.12.
Example 3:
A recipe calls for
cups of flour to make servings for 6 people. How much
11
2
flour should be used to make servings for 4 people?
Solution:
Using x for the flour required for 4 people, the following proportion can be
written.
6 people
4 people
11
2
cups
x
The product of the extremes is (6)(x) = 6x.
The product of the means is
.
(4) 11
2
6
Rev. 0
Page 15
MA-02
