The sum of three numbers is 79. The third number is 2 times the second. The first number is 5 less than the second. What are the numbers?

first = 21 - 5 = 16

second = 21

Third = 21*2 = 42

Step-by-step explanation:

first + second + third = 79

Let the second number = x

third = 2*x

first = x - 5

So we get

x - 5 + x + 2x = 79

4x - 5 = 79 Add 5

4x - 5 + 5 = 79 + 5 Combine

4x = 84 Divide by 4

4x/4 = 84/4

x = 21