2022 · Q20
The value of a 2-digit number is 5 times the sum of the digits. What is the product of the digits?
Elementary MathematicsNumber System
- A15
- B18
- C20
- D27
Explanation
10a+b = 5(a+b) gives 5a = 4b, so the digits are a = 4, b = 5. Their product is 20. The keyed option is C.