In a probability experiment, Craig rolled a six-sided die 55 times. The die landed on a number greater than three 31 times. What is the ratio of rolls greater than three to rolls less than or equal to three?

A. 31/24

B. 55/31

C. 24/31

D. 31/55

The answer is A because:

rolls greater than three/rolls less than or equal to three

rolls greater than three: 31

rolls less than or equal to three: 55-31 = 24

rolls greater than three/rolls less than or equal to three = 31/24

31/55 times he rolled a number greater than 3.

Either you roll a number > 3, or you roll a number ≤3.

55/55 - 31/55 = 24/55 times he rolled a number less than or equal to 3.

Now we want the ratio of 31/55 to 24/55.

Mutliply each side by 55 and we get 31/24.