The sum of three numbers is 70. The third number is 2 times the second. The first number is 10 less than the second. What are the numbers?

1 answer

Let's call the second number "x".

According to the problem, the third number is 2 times the second:

Third number = 2x

The first number is 10 less than the second:

First number = x - 10

And we know that the sum of all three numbers is 70:

First number + Second number + Third number = 70

Now we can substitute the expressions we found for the first, second, and third numbers into this equation:

(x - 10) + x + (2x) = 70

Simplifying:

4x - 10 = 70

Adding 10 to both sides:

4x = 80

Dividing both sides by 4:

x = 20

So the second number is 20.

Now we can use the expressions we found earlier to find the first and third numbers:

First number = x - 10 = 20 - 10 = 10

Third number = 2x = 2(20) = 40

So the three numbers are 10, 20, and 40.