How many 3-digit numbers divisible by 5 can be formed from the digits 0, 1, 2, 3, 4 and 5 if no digit is repeated in a number?

Case 1 — units digit 0: the hundreds place has 5 choices (1-5) and the tens place 4 left, giving 20. Case 2 — units digit 5: the hundreds place cannot be 0, so it has 4 choices, and the tens place has 4 left, giving 16. Total = 20 + 16 = 36. The value 40 comes from forgetting that a number cannot begin with 0.