Question

What two numbers added equal 40 but when subtracted equal 10?

Answer 1

Answer:

25 and 15

You can easily make a system of equations:

x + y = 40

x - y = 10

Solving for x on equation 2 gets x = 10 + y.

Plugging in this into the first equation, you get 10 + y + y = 40

Thus, 10 + 2y = 40

y = 15.

Plugging this back into either equation gets x = 25.