The Sum of Two Numbers is 18 and Their Difference is 4

The sum of two numbers is 18 and their difference is 4. 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 18. In other words, x plus y equals 18 and can be written as equation A:

x + y = 18

The difference between x and y is 4. In other words, x minus y equals 4 and can be written as equation B:

x - y = 4

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

x - y = 4
x = 4 + y

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

x + y = 18
4 + y + y = 18
4 + 2y = 18
2y = 14
y = 7

Now we know y is 7. Which means that we can substitute y for 7 in equation A and solve for x:

x + y = 18
x + 7 = 18
X = 11

Summary: The sum of two numbers is 18 and their difference is 4. What are the two numbers? Answer: 11 and 7 as proven here:

Sum: 11 + 7 = 18
Difference: 11 - 7 = 4

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The Sum of Two Numbers is 18 and Their Difference is 5
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