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Last Updated on May 3, 2023
GMAT OFFICIAL GUIDE PS
Solution:
We are given that the ratio of students to teacher is 30 to 1. We can rewrite this using variable multipliers.
students : teachers = 30x : x
We are next given that student enrollment increases by 50 and the number of teachers increases by 5. With this change the new ratio becomes 25 to 1. We can put all this into an equation:
Students/Teachers 25/1 = (30x + 50)/(x + 5)
If we cross multiply we have:
25(x + 5) = 30x + 50
25x + 125 = 30x + 50
75 = 5x
15 = x
Since x is the present number of teachers, currently there are 15 teachers.
Answer: E
