Question

The sum of three numbers is 72. The second number is 7 times the first. The third number is 18 less than the second. What is the first number

Answer 1

Define x:

Let the first number be x

Second number = 7x

Third number = 7x - 18

Solve x:

The sum of the 3 numbers is 72

x + 7x + (7x - 18) = 72

x + 7x + 7x - 18 = 72

15x - 18 = 72

15x = 90

x = 90 ÷ 15 = 6

Find the first number:

First number = x = 6

Answer: The first number is 6