How many students were surveyed?

Question

A class is surveyed.  1/4 of the students like blue, 1/8 of the students like red, and 3/5 of the remaining students like green.  If 15 students like green, how many students were surveyed?

Answer 1

1/4 + 1/8 = 2/8 + 1/8 = 3/8, the remaining students is therefore 1-3/8 = 8/8 - 3/8 = 5/8

 

3/5 of this remaining students is 3/5 of 5/8, or 3/5 * 5/8 = 3/8

 

If 3/8 of the surveyed class is equal to 15, then the whole class size is equal to 15 divided by 3/8, or 15 * 8/3 = 40

 

The answer therefore is 40 students

 

remember, when dividing by a fraction you invert the fraction and multiply.