Question

In a 3-digit number, the hundreds digit is four more than the units digit, and the tens digit is three more then the sum of the other digits. Find the three digits if the sum of all three digits is 15. Then find the number.

Answer 1

591

Explanation:

Let's use algebra to solve this question:

Units digit = x

Hundreds digit = x+4

Tens digit = 3 + (x+4) + x = 2x +7

All 3 digits = 15

so x + (x+4) + 2x + 7 = 15

4x +11 =15

4x = 4

x = 1

Then you substitute:

Units = 1

Hundreds = 1+4 = 5

Tens = 2(1) + 7 = 2 + 7 = 9

The number is therefore 591.