The Sum of Two Numbers is 81 and Their Difference is 8

The sum of two numbers is 81 and their difference is 8. 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 81. In other words, x plus y equals 81 and can be written as equation A:

x + y = 81

The difference between x and y is 8. In other words, x minus y equals 8 and can be written as equation B:

x - y = 8

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

x - y = 8
x = 8 + y

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

x + y = 81
8 + y + y = 81
8 + 2y = 81
2y = 73
y = 36.5

Now we know y is 36.5. Which means that we can substitute y for 36.5 in equation A and solve for x:

x + y = 81
x + 36.5 = 81
X = 44.5

Summary: The sum of two numbers is 81 and their difference is 8. What are the two numbers? Answer: 44.5 and 36.5 as proven here:

Sum: 44.5 + 36.5 = 81
Difference: 44.5 - 36.5 = 8

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The Sum of Two Numbers is 81 and Their Difference is 9
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