The Sum Of Two Numbers Is 51 And Their Difference Is 21

The problem given says that 2 unknown numbers are given, whose sum is equal to 51 and the difference is 21. Let's find the two numbers :

When we add the two numbers :
X + Y = 51

The difference of two numbers :
X - Y = 21

Solution :

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

X + Y = 51
X - Y = 21

2X = 72

Let's divide 72 to 2 for the first number "X" .

X/2 = 36

First number is 36

X + Y = 51
So ;
36 + Y = 51
Y = 51 - 36
Y = 15

Second number is 15

Question & Answer
The Sum Of Two Numbers Is 51 And Their Difference Is 21 : 36 And 15