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?
About 157 seventh-grade students would like to snorkel.
About 202 seventh-grade students would like to snorkel.
About 630 seventh-grade students would like to snorkel.
About 720 seventh-grade students would like to snorkel.

Question

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? 
About 157 seventh-grade students would like to snorkel.
About 202 seventh-grade students would like to snorkel. 
About 630 seventh-grade students would like to snorkel.
About 720 seventh-grade students would like to snorkel.

jhonyy9 · Answer

use the rule of 3 simple

given that 7 out of 9 snorkeling

from 9 snorkeling 7 students 
from 810 snorkel x

x = 810×7/9 = 630 students

hope is understandably and helped