To find the denominator we find the total number of students. 35 + 13 + 22 + 10 = 80. The numerator is the number of students for Website A. Now we got a fraction 35/80. Now to simplify it we keep dividing 35 and 80 till we can't divide it anymore without going into decimals. 35 / 5 = 7. 80 / 5 = 16. We got 7/16. We can't divide it anymore because 7 is a prime number. So there's your answer. 7/16.