The Sum of Two Numbers is 90 and Their Difference is 4

The sum of two numbers is 90 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 90. In other words, x plus y equals 90 and can be written as equation A:

x + y = 90

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 = 90
4 + y + y = 90
4 + 2y = 90
2y = 86
y = 43

Now we know y is 43. Which means that we can substitute y for 43 in equation A and solve for x:

x + y = 90
x + 43 = 90
X = 47

Summary: The sum of two numbers is 90 and their difference is 4. What are the two numbers? Answer: 47 and 43 as proven here:

Sum: 47 + 43 = 90
Difference: 47 - 43 = 4

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The Sum of Two Numbers is 90 and Their Difference is 5
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