GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
GRE Prep Club Team Member
Joined: 20 Feb 2017
Posts: 2512
Given Kudos: 1060
GPA: 3.39
In a certain class of students, 25% received A’s on the final exam and
[#permalink]
01 Apr 2021, 06:30
01 Apr 2021, 06:30
Expert Reply
1
Bookmarks
00:00
Question Stats:
83% (01:46) correct
16% (02:54) wrong based on 6 sessions
Hide Show timer Statistics
In a certain class of students, 25% received A’s on the final exam and 2/3 of these students received A’s in the class as a whole. If 15 students in the class received A’s on the final exam but did not receive an A in the class, how many students did not receive an A on the final exam?
A. 45
B. 60
C. 105
D. 135
E. 180
A. 45
B. 60
C. 105
D. 135
E. 180
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Given Kudos: 172
Location: India
WE:Education (Education)
Re: In a certain class of students, 25% received A’s on the final exam and
[#permalink]
02 Apr 2021, 08:10
02 Apr 2021, 08:10
GeminiHeat wrote:
In a certain class of students, 25% received A’s on the final exam and 2/3 of these students received A’s in the class as a whole. If 15 students in the class received A’s on the final exam but did not receive an A in the class, how many students did not receive an A on the final exam?
A. 45
B. 60
C. 105
D. 135
E. 180
A. 45
B. 60
C. 105
D. 135
E. 180
Let the total number of students in the class be \(x\)
Students with A \(= 0.25x\)
Students with not an A \(= 0.75x\)
Now, Students with an A in the class \(= \frac{2}{3}(0.25x)\)
So, Students with not an A in the class \(= \frac{1}{3}(0.25x) = 15\)
\(0.25x = 45\)
\(x = 180\)
Therefore, Students with not an A \(= 0.75x = 0.75(180) = 135\)
Hence, option D
Re: In a certain class of students, 25% received A’s on the final exam and
[#permalink]
04 Apr 2021, 05:29
04 Apr 2021, 05:29
1
Here,
Since, \(\frac{2}{3} \) of students received A in the class as whole, so \(\frac{1}{3}\) of students received A in final but not in class as whole and they are = 15 students
25 % received A on final exam
Let the total number of student = x
we can re-write the equation as -
\( \frac{1}{4 }* \frac{1}{3} * x = 15 \)
or \(x = 180\)
Since 25% received A , therefore 75% didnot received A ,
i.e = \(\frac{3}{4}\) * 180 = 135
SECOND METHOD: -
Let pick an answer from the given answer, (we can start for C or D and move up or down accordingly)
Let us choose C, which is = 105 ( total number of students didn't received A)
i.e \(\frac{3}{4 } x = 105 \)
or \(x = 140 \)
25% of 140 = 35
and \( \frac{2}{3 } * 35 = \frac{70}{3}\)
check {\(35 - (\frac{75}{3}) \)} < 15 students , which donot match as per the information provided in question. Hence option C is not our answer ( also note 35 - 75/ 3 = almost 11, so we move down to option D)
so we need to move to option D, which is 135 students
now,
\(\frac{3}{4 } * x = 135\)
or x = 180
25% of 180 = 45
and \(\frac{2}{3} * 45 = 30\)
check 45 - 30 = 15 students students in the class received A’s on the final exam but did not receive an A in the class ( which is given )
Hence option D is our answer
Since, \(\frac{2}{3} \) of students received A in the class as whole, so \(\frac{1}{3}\) of students received A in final but not in class as whole and they are = 15 students
25 % received A on final exam
Let the total number of student = x
we can re-write the equation as -
\( \frac{1}{4 }* \frac{1}{3} * x = 15 \)
or \(x = 180\)
Since 25% received A , therefore 75% didnot received A ,
i.e = \(\frac{3}{4}\) * 180 = 135
SECOND METHOD: -
Let pick an answer from the given answer, (we can start for C or D and move up or down accordingly)
Let us choose C, which is = 105 ( total number of students didn't received A)
i.e \(\frac{3}{4 } x = 105 \)
or \(x = 140 \)
25% of 140 = 35
and \( \frac{2}{3 } * 35 = \frac{70}{3}\)
check {\(35 - (\frac{75}{3}) \)} < 15 students , which donot match as per the information provided in question. Hence option C is not our answer ( also note 35 - 75/ 3 = almost 11, so we move down to option D)
so we need to move to option D, which is 135 students
now,
\(\frac{3}{4 } * x = 135\)
or x = 180
25% of 180 = 45
and \(\frac{2}{3} * 45 = 30\)
check 45 - 30 = 15 students students in the class received A’s on the final exam but did not receive an A in the class ( which is given )
Hence option D is our answer
