At Cambridge Junior School, there are 90 students who represent x% of

Question

Weekly Quant Quiz Question - 3

At Cambridge Junior School, there are 90 students who represent x% of total boys at the school. If the total no of boys at the school make up 40% of the total students x. Find the value of x.
a) 100
b) 120
c) 150
d) 200
e) Can not be determined.

Gladiator59 · Accepted Answer

Please find my solution in attached image, IMO Option C is correct.

vipulshahi · Answer

x% of B = 90

40% of Total Student = B(Total no. Of Boys)

While substutuing the valve , Total No. Of students = 150

sananoor · Answer

90 = x/100 * (40/100)x---->solving this gives u 150
C is answer

Manvi_nagpal · Answer

90= \frac{xb}{100}  and b=  {40x}{100}  
therefore 90= {40x^2}/10000
so x=150 
C

u1983 · Answer

90=(x/100)(40/100)x ==>x=150  Ans C

akshaykotha · Answer

Let total boys be B.

x% of B = 90

40% of x = B

x/b *100 = 90; 40/100 *x = b which leads to no where.

Answer E - cannot be determined.

cancerian · Answer

Total boys =T
So based on the question stem,90=(x/100)*T
and Based on 2nd stem: T=0.4x

On solving 2 equations, taking positive root for x,answer is 150 I.e C

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honneeey · Answer

90=X% * b
900=bx
B=40%*x
Substituting we get x=150
Answer-C

DesyKristine · Answer

E.

The number of boys is represent the number for xpercent of total boys at cambridge university it's not represent the number of total boys, we had to now the value of xpercent to know the total boys at that school. And the question how much is the total students, and we can't determine the total numbers of the students if we can't determine the number of total boys at that school.

size=80]  Posted from my mobile device

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shivangibh · Answer

x% of boys = 90
boys= (90/x)*100 ... (1)

40% of x = boys ... (2)

(90/x)*100 = 40% * x
x^2 = (90*100*100)/40
x= 150 (avoid negative root)

Princ · Answer

OA:C

90 = \frac{x}{100}* Total boys ...(1)

Total boys  = \frac{40}{100}*Total \quad Students = \frac{40}{100}*x  ....(2)

Putting value of Total boys from (2) into (1), we get

90=\frac{x}{100}* \frac{40}{100}*x

x^2=\frac{90}{40}*100^2

x= \frac{3}{2}*100=150

mongmat27 · Answer

Let total boys be y.

90 = (x/100) * y
xy = 9000

y = (40/100)*x

Thus, x* x*(40/100) = 9000

On simplication, we get,

4*x*x = 90000

Taking square root on both sides,

2x = 300
x = 150

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santorasantu · Answer

Let b be the number of boys

90 = (x/100)*B

B=(40/100)*x

90=(x/100)*(40/100)*x

x=150

Therefore C

mitusingla · Answer

90 students at the school represent x% of #boys

#boys are 40% of total students.

#total students not known as 90 is not given to be THE #students in the school.

so, #boys cannot be determined.

piermacabj · Answer

My problem with having 150 as the answer is that it does not make any sense. They are telling you that 90 Is "some" percentage of the boys, and that the total percentage of the boys is 40% of the students, meaning that the 40% is equal or greater that 90. With that alone you can tell that the 100% is going to be more that 150. At minimum, the total amount of students would be 225, which happens when you take de 40% of boys as 90 and solve like this:

40/100 * x = 90
x = 225

But then again, that would be the minimum, so the answer should be "E" in my opinion.

40/100 * x = 90 
x = 225

But then again, that would be the minimum, so the answer should be "E" in my opinion.

At Cambridge Junior School, there are 90 students who represent x% of

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GMAT Problem Solving (PS) Questions

At Cambridge Junior School, there are 90 students who represent x% of

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

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Perfect 805 Score Debrief by Julia

My Rewards