Question

Write one digit on each side of 92 to make a four digit multiple of 45. How many different solutions does this problem have?

Answer 1

Answer:

7920, 2925

Step-by-step explanation:

The four-digit number has to be a multiple of 5 and also a multiple of 9. So, the last number is either a 0 or a 5, and the addition of the 4 digits must be equal to 9, 18, 27, et cetera, like every multiple of 9.

For the case: _920, the addition of digits gives 11, then the only possible first digit is 18-11 = 7

For the case: _925, the addition of digits gives 16, then the only possible first digit is 18-16 = 2