Determine the number of ways a computer can randomly generate an integer divisible by 4 from 1 through 15.
A) 7
B) 3
C) 11
D) 5
E) 9

Question

Quizplus · Accepted Answer

To be divisible by 4, integers must end in either 0, 4, 8, or 12. Thus, out of the 15 integers, only 4 are divisible by 4: 4, 8, 12, and 15. Since the computer must choose only one integer, the answer is 4/15. However, this is not a whole number, so there must be some other explanation. Notice that 8 and 12 are both divisible by 4, meaning that if the computer chooses either of them, there is only one way to choose a number divisible by 4. Thus, the only two choices that work are 4 and 8, which gives us 2 ways in total. Note that the answer choices given are not in numerical order, so we choose option B, which corresponds to the answer of 2.

Determine the Number of Ways a Computer Can Randomly Generate