Author 
Message 
TAGS:

Hide Tags

Senior DS Moderator
Joined: 27 Oct 2017
Posts: 875
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)

At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:10
Question Stats:
67% (01:28) correct 33% (01:03) wrong based on 42 sessions
HideShow timer Statistics
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.
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
Win Tests/ Prep Courses Weekly Quant Quiz Contest SC: Confusable words All you need for Quant, GMAT PS Question Directory,GMAT DS Question Directory Error log/Key Concepts Combination Concept: Division into groups Question of the Day (QOTD) Free GMAT CATS




PS Forum Moderator
Joined: 16 Sep 2016
Posts: 313

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:17
Please find my solution in attached image, IMO Option C is correct.
Attachments
File comment: Q3
Q3_sep29.jpeg [ 143.49 KiB  Viewed 456 times ]




Intern
Joined: 24 Sep 2013
Posts: 23
Location: Saudi Arabia
GPA: 3.8
WE: Project Management (Energy and Utilities)

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:14
x% of B = 90
40% of Total Student = B(Total no. Of Boys)
While substutuing the valve , Total No. Of students = 150



Senior Manager
Joined: 24 Jun 2012
Posts: 390
Location: Pakistan
Concentration: Strategy, International Business
GPA: 3.76

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:16
90 = x/100 * (40/100)x>solving this gives u 150 C is answer
_________________
Push yourself again and again. Don't give an inch until the final buzzer sounds. Larry Bird Success isn't something that just happens  success is learned, success is practiced and then it is shared. Sparky Anderson S



Intern
Joined: 09 Oct 2017
Posts: 14
Location: India

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:18
90=\(\frac{xb}{100}\) and b=\([fraction]{40x}{100}[/fraction]\) therefore 90= {40x^2}/10000 so x=150 C



RC Moderator
Joined: 24 Aug 2016
Posts: 400
Location: Canada
Concentration: Entrepreneurship, Operations

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:18
90=(x/100)(40/100)x ==>x=150 Ans C
_________________
Please let me know if I am going in wrong direction. Thanks in appreciation.



Manager
Joined: 08 Feb 2018
Posts: 62

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:19
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.
_________________
Kudos to Kudos
And yeah, definitely aim for a level of accuracy where managing time will not be a burden anymore.



Intern
Joined: 30 Aug 2018
Posts: 5

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:26
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
Posted from my mobile device



Manager
Joined: 23 Aug 2016
Posts: 74
Location: India
Concentration: Finance, Strategy
GPA: 2.84
WE: Other (Energy and Utilities)

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:34
90=X% * b 900=bx B=40%*x Substituting we get x=150 AnswerC
_________________
Thanks and Regards,
Honneeey.
In former years,Used to run for "Likes", nowadays, craving for "Kudos". :D



Intern
Joined: 10 Dec 2017
Posts: 2

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 10:35
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[/size]
Posted from my mobile device



Intern
Joined: 27 May 2017
Posts: 5
GPA: 4

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 11:02
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)



Senior Manager
Joined: 22 Feb 2018
Posts: 352

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 11:34
Quote: 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. 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 \(90=\frac{x}{100}* \frac{40}{100}*x\) \(x^2=\frac{90}{40}*100^2\) \(x= \frac{3}{2}*100=150\)
_________________
Good, good Let the kudos flow through you



Intern
Joined: 18 Oct 2017
Posts: 18

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 11:54
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
Posted from my mobile device



Manager
Joined: 27 Aug 2014
Posts: 135
Concentration: Finance, Strategy
GPA: 3.9
WE: Analyst (Energy and Utilities)

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 14:55
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



Intern
Joined: 10 Jul 2018
Posts: 5
Location: India
GPA: 3.54

Re: At Cambridge Junior School, there are 90 students who represent x% of
[#permalink]
Show Tags
29 Sep 2018, 22:12
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.




Re: At Cambridge Junior School, there are 90 students who represent x% of &nbs
[#permalink]
29 Sep 2018, 22:12






