Question

When Henry surveyed 45 seventh-grade students at random in the school cafeteria, he found that 3 out of 15 liked reggae music. Using proportional reasoning, about how many of the 180 seventh-grade students in his school like reggae?

Answer 1

3                       x
---------= --------- ---------
15                 180

15x=540
-----   ------= 36 students. 
15       15

Steps: Cross multiply to get 15x and 540. Divide both numbers by 15, then you found what x equals, which is the answer.