Let first number be x.
Let second number be y.
According to question,
x+y=36…….(equation 1)
and
x-y=6…..(equation 2)
equation 2 can be written as , x=6+y……(equation 3)
Put equation 3 in equation 1,
6+y+y=36
6+2y=36
2y=36–6
2y=30
y=30/2
y=15
now, put y=15 in equation 1,
x+15=36
x=36–15
x=21
So, numbers are 21 and 15.
