Question

A total of 360 teachers and pupils participated in tree planting. Each teacher planted 3 trees and each group of 3 pupils planted 2 trees. If 520 trees were planted altogether, how many pupils were there?

Answer 1

if 3 pupils planted 2 trees,it means that 1 tree was planted by 1 1/2 pupils(imagine).so 1 tree was planted by 3/2 pupil and 1 teacher.
so the ratio from teacher to pupil is 1:3/2 which is nothing but 2:3.
teachers=2/5 * 520=208
pupils=3/5 * 520=312


Hope you understood...:))

Answer 2

Number of teachers=120 ,Number of pupils =240