The product is the answer when you multiply two numbers together. So, since Hasni is 4 years older than Alia, we need to find two numbers that are 4 apart that make 32 when we multiply them.
This gives us 8 and 4, and since Hasni js 4 years older than Alia, Hasni must be 8 years old and Alia must be 4 years old.
