Question

The sum of 2 numbers is 15, and their difference is 3. Therefore, the numbers are ______.

Options

• (17, −2)

• (8, 7)

• (9, 6)

• (6, 9)

Answer 1

The sum of 2 numbers is 15, and their difference is 3. Therefore, the numbers are (9, 6).

Explanation:

Let the two numbers be x and y such that:

x + y = 15     ...(1)

x − y = 3     ...(2)

Adding equations (1) and (2):

(x + y) + (x − y) = 15 + 3

2x = 18

x = `18/2`

∴ x = 9

Substitute x = 9 into (1):

9 + y = 15

y = 15 − 9

∴ y = 6

So, the two numbers are 9 and 6.