Question

Find two numbers if their sum is 7.2 and their difference is 2.7.

Answer 1

The two numbers are 4.95 and 2.25.

Explanation:

Let the two numbers be x and y. Given conditions,

$x+y = 7.2$ ...............................(1)

$x-y = 2.7$................................(2)

Adding equations (1) and (2), we get

$LHS = x+y+x-y = (2x - y+y) = 2x\\RHS=7.2+2.7 = 9.9$

Therefore $2x = 9.9; x=9.9/2 = 4.95$

x=4.95 .......................(3)

Substituting value of x from (3) in (1), we get

$x+y = 7.2\\4.95+y=7.2\\y=7.2-4.95 = 2.25$

y=2.25 ........................(4)

From (3) and (4), the two numbers are 4.95 and 2.25.