The Sum Of Two Numbers Is 21 And Their Difference Is 5

The problem given says that 2 unknown numbers are given, whose sum is equal to 21 and the difference is 5. Let's find the two numbers :

When we add the two numbers :
X + Y = 21

The difference of two numbers :
X - Y = 5

Solution :

If we add the two equations eachother , then we can find the first number.

X + Y = 21
X - Y = 5

2X = 26

Let's divide 26 to 2 for the first number "X" .

X/2 = 13

First number is 13

X + Y = 21
So ;
13 + Y = 21
Y = 21 - 13
Y = 8

Second number is 8

Question & Answer
The Sum Of Two Numbers Is 21 And Their Difference Is 5 : 13 And 8