The Sum of Two Numbers is 20 and Their Difference is 1

The sum of two numbers is 20 and their difference is 1. 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 20. In other words, x plus y equals 20 and can be written as equation A:

x + y = 20

The difference between x and y is 1. In other words, x minus y equals 1 and can be written as equation B:

x - y = 1

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

x - y = 1
x = 1 + y

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

x + y = 20
1 + y + y = 20
1 + 2y = 20
2y = 19
y = 9.5

Now we know y is 9.5. Which means that we can substitute y for 9.5 in equation A and solve for x:

x + y = 20
x + 9.5 = 20
X = 10.5

Summary: The sum of two numbers is 20 and their difference is 1. What are the two numbers? Answer: 10.5 and 9.5 as proven here:

Sum: 10.5 + 9.5 = 20
Difference: 10.5 - 9.5 = 1

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The Sum of Two Numbers is 20 and Their Difference is 2
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