Question

On a school trip, the ratio of the teachers to students is 2:21. The ratio boys to girls is 4:3. If there are 18 girls girls on the trip, how many teachers are there?

Answer 1

4

Explanation:

Let's say B is the number of boys and T is the number of teachers.

T / (B + 18) = 2/21

B/18 = 4/3

Solve the second equation for B.

B = 24

Plug into the first equation to find T.

T / (24 + 18) = 2/21

T = 4