Question

The sum of two numbers is 72. The difference of the two numbers is 40. What are the two numbers.

Let
x
be the larger number and
y
be the smaller number.
Write an equation that expresses the information in the sentence "The sum of two numbers is 72."

Answer 1

Explanation:

x + y = 72

x - y = 40

x = y + 40

so, the first equation is then

y + 40 + y = 72

2y + 40 = 72

2y = 32

y = 16

x = y + 40 = 16 + 40 = 56