When Andrei surveyed 36 random seventh-grade students in the lunchroom, he found that 7 out of 9 would like to try or have already tried snorkeling. Using proportional reasoning, about how many of the 810 seventh-grade students in his school would like to snorkel?
A. About 157 seventh-grade students would like to snorkel.
B. About 202 seventh-grade students would like to snorkel.
C. About 630 seventh-grade students would like to snorkel.
D. About 720 seventh-grade students would like to snorkel.

Respuesta :

You can use equivalent ratios to create a proportion in order to find the approximate number of students that would like to snorkel.

Student who like to snorkel        7         x
Total # of students                     9   =   810

You can use multiplication to create an equivalent ratio.  To get from 9 to 810, you will need 90 groups.  This means you will have about 90 groups of 7 students who would like to snorkel.  

90 x 7 = 630 students.

Choice C is correct.
The answer is about 630 students would like to snorkel.