Question

Seventy- five percent, or 15 of the students in Emily’s home room class are going on a field trip. Two thirds, or 12 of the students in Santiago’s home room class are going on a field trip. Which class has more students? Justify your answer.

Answer 1

Emily has 20 students and Santiago has 18 students in home rooms

Explanation:

to figure out the number in Emily's class we need to answer this question - '15 is 75% of what number'?

we can use:

is/of = %/100

is = 15

of = 'n'

75% = 75/100 or 3/4

15/n = 3/4

cross-multiply to get:

3n = 60

n = 20

So there are 20 students in Emily's home room

Now we find the number of students in Santiago's home room:

the question is - '12 is 2/3 of what number'?

we can write this equation:

12 = 2/3n

multiply each side by 3/2 to get:

36/2 = n

18 = n

18 students in Santiago's home room