Question

U. 3. Two numbers have a sum of 139 and a difference of 31. Which is one of the numbers? A 85 B. 91 C. 100 D. 108

Answer 1

Let the larger number be x

Let the smaller number be y

We were told that the two numbers have a sum of 139. This means that

x + y = 139

x = 139 - y

Also, we were told that the difference of the numbers is 31. This means that

x - y = 31

Substituting x = 139 - y into x - y = 31, we have

139 - y - y = 31

- y - y = 31 - 139

- 2y = - 108

y = - 108/-2

y = 54

x = 139 - y = 139 - 54

x = 85

Thus, one of the numbers is 85