The Sum of Two Numbers is 10 and Their Difference is 7

The sum of two numbers is 10 and their difference is 7. What are the two numbers? Let's start by calling the two numbers we are looking for x and y.

The sum of x and y is 10. In other words, x plus y equals 10 and can be written as equation A:

x + y = 10

The difference between x and y is 7. In other words, x minus y equals 7 and can be written as equation B:

x - y = 7

Now solve equation B for x to get the revised equation B:

x - y = 7
x = 7 + y

Then substitute x in equation A from the revised equation B and then solve for y:

x + y = 10
7 + y + y = 10
7 + 2y = 10
2y = 3
y = 1.5

Now we know y is 1.5. Which means that we can substitute y for 1.5 in equation A and solve for x:

x + y = 10
x + 1.5 = 10
X = 8.5

Summary: The sum of two numbers is 10 and their difference is 7. What are the two numbers? Answer: 8.5 and 1.5 as proven here:

Sum: 8.5 + 1.5 = 10
Difference: 8.5 - 1.5 = 7

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The Sum of Two Numbers is 10 and Their Difference is 8
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