Question

If repetition of digits is allowed, how many different ways 5-digit codes are possible with the condition that the first digit should be a multiple of 3 and the last digit cannot be zero.

a. 17496.
b. 27000.
c. 18000.
d. 30000.

Answer 1

b) 27,000

Explanation:

3 × 10 × 10 × 10 × 9 = 27000

'3' because the first digit can only be 3,6, or 9

'9' because the last digit cannot be zero, leaving only 9 options