The sum of two numbers is 40 and their difference is 4. What is their product?
Answer: B
Let the two numbers be x and y.
Given, x + y = 40 and x - y = 4.
Adding the two equations: 2x = 44, so x = 22.
Substituting x = 22 in the first equation: 22 + y = 40, so y = 18.
Their product is x × y = 22 × 18 = 396.