Question

The ratio of boys to girls in Mr.Watson’s class is 2 to 3. There are 18 girls in his class. What is the total number of students in the class?
If the ratio of boys and girls were the same in the whole school, would it be possible that there were a total of 306 boys and 459 girls in the entire school? Why or why not?

Answer 1

Let's read this in a more proper way.

The number of boys in Mr. Watson's class is 2/3 the number of girls. So:

$18 * \frac{2}{3} = 12\\18 + 12 = 30$

There are 30 students in Mr. Watson's class.

For this ratio to be in true in the second problem (306 boys, 459 girls), 306 must be 2/3 of 459.

$459 * \frac{2}{3} = 306$

The ratio holds true for the second problem.

30 students,

Yes it is possible, because 306 is 2/3 of 459.