At a certain high school, the student to teacher ratio is 25:1. If the

Question

At a certain high school, the student to teacher ratio is 25:1. If the number of students increases by 50% and 10% of teachers are laid off, what would be the new student to teacher ratio? (Assume that no other changes happen)

A. 40:1
B. 125:3
C. 75:2
D. 145:9
E. Cannot be determined

A. 40:1
B. 125:3
C. 75:2
D. 145:9
E. Cannot be determined

kill3rlook5 · Accepted Answer

Ratio of student:teacher = 25:1 Let common Factor be x. So no of students:Tecaher will be 25x:1x

Now Number of students = 25x+(50%*25x) = 75x/2
Number of teachers = x-(10x/100)=9x/10

Student:Teacher Ratio will be (75x/2)/(9x/10) = 125:3

Hence answer is B.

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Luckisnoexcuse · Answer

2500:100
3750:90
375:9
125:3

250:10
375:9
125:3

500:20
750:18
125:3

B

septwibowo · Answer

- 10% teacher is the key. We should plug in the value that give the integer for 10% of teacher.
- Let say number of teacher = 10 (10 times the ratio), so the number of stundent = 25*10 = 250.
- Students increase 50% ->  250*1.5  = 375 students
- Teacher laid off 10% ->  10*0.9 = 9 teachers.
- New ration =  \frac{375}{9} , divide by 3 =  \frac{125}{3}

B.

JeffTargetTestPrep · Answer

We have a current ratio of 25/1 = students to teachers. After 50% more students arrive and 10% of the teachers are laid off, we have:

25(1.5)/0.9 = 37.5/0.9 = 375/9 = 125/3

Alternate Solution:

Let’s say there were 250 students and 10 teachers. After 50% more students arrive, there will be 250 + 125 = 375 students. After 10% of the teachers are laid off, there will be 10 - 1 = 9 teachers. Thus, the new ratio will be 375/9 = 125/3.

Answer: B

giovannisumano · Answer

\frac{25*1.5}{1*.9} = \frac{25*15}{9}= \frac{25*5*3}{3*3} = \frac{25*5}{3} = \frac{125}{3} , thus the new ratio of students to teaches is 125:3

ablatt4 · Answer

I would recommend just plugging in a number of students to teachers that work within the ratio given and then compare.

Looking ahead we see a 50% increase in students and a 10% decrease in teachers. Let us just assume the actual ratio is 250:10

If we increase the students 50% and decrease teachers 10% the new ratio is 375:9

This isn't an answer choice so we must simplify, 375 is not divisible by 9 but is divisible by 3.

We can reduce to 125:3

B

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