What is the sum of two numbers is 40 and their difference is 10

The two numbers are 25 and 15.

Step-by-step explanation:

Let's find out the two numbers, this way:

x = first number

y = second number

This is the equations system:

x + y = 40

x - y = 10

Solving for x in the first equation:

x + y = 40

x = 40 - y

Solving for y in the second equation:

40 - y - y = 10

40 - 2y = 10

-2y = 10 - 40

-2y = - 30

y = - 30/-2 = 15

Solving for x:

x + y = 40

x + 15 = 40

x = 40 - 15

x = 25

The two numbers are 25 and 15.