The sum of two numbers is 30 and their difference is 12, what are the two numbers

Step-by-step explanation:

Let the number is a and b

The sum of two numbers =30

so,a+b=30 ............(1)

The difference of two number =12

so,a-b=12 .................(2)

If we add two equation (1) and (2)

we get,

a+b+a-b=30+12

2a=42

so,one number is a=21

if we put the value a in (2) equation

we get,

a-b=12

21-b=12

b=21-12

b=9

so,the another number is=b=9

Sum: 21 + 9 = 30

Difference: 21 - 9 = 12