Tip
A factor of a number n is any integer that divides exactly into the number n. The number n is divisible by each of its factors. A prime number p is any integer with exactly two factors: 1 and p. An even number is an integer with the digit 0, 2, 4, 6, or 8 in the ones place. An odd number is an integer with the digit 1, 3, 5, 7, or 9 in the ones place.
Sample Problem
Which of the following is divisible by 15?
Answer Options
(A) 159
(B) 225
(C) 415
(D) 560
(E) 663
View Correct Answer
(B) 225
Numbers that are divisible by 15 are divisible by 3 and by 5. Only 225, 415, and 560 are divisible by 5. Of these three numbers, only 225 is also divisible by 3. So 225 is divisible by 15.
