The sum of two numbers is 40 and their difference is 6.5 what is their product

Let x = first number, and y = second number.

x + y = 40 (1)

x - y = 6.5 (2)

Rearrange (2)

y = x - 6.5 (3)

Sub (3) in (1)

x + (x - 6.5) = 40

2x - 6.5 = 40

2x = 33.5

x = 16.75 (4)

Sub (4) in (1)

16.75 + y = 40

y = 23.25

x * y = 16.75 * 13.25 = 221.9375

The product is 221.9375