GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 22 Aug 2018, 00:54

### GMAT 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

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Torry has submitted 2/5 of his homework assignments, and he received a

Author Message
TAGS:

### Hide Tags

Intern
Affiliations: Emerson Electric
Joined: 08 Sep 2013
Posts: 1
Location: China
GMAT Date: 02-02-2015
GPA: 3.5
WE: Operations (Manufacturing)
Torry has submitted 2/5 of his homework assignments, and he received a  [#permalink]

### Show Tags

Updated on: 20 Oct 2014, 04:29
1
15
00:00

Difficulty:

45% (medium)

Question Stats:

66% (01:46) correct 34% (02:03) wrong based on 219 sessions

### HideShow timer Statistics

Torry has submitted 2/5 of his homework assignments, and he received an average grade of 75 for those assignments. If he wishes to receive an average grade of 90 for all his homework assignments, the average grade for Torry's remaining homework assignments must be what percent greater than the average grade for the assignments he has already submitted?

A. 15%
B. 20%
C. 25%
D. 33 1/3%
E. 40%

My faulty solution:
First two HW assignments: x1 + x2 = 2*0.75
Wish five HW assignments: (x1 + x2) + (x3 + x4 + x5) = 5*0.9
2*0.75 + (x3 + x4 + x5) = 5*0.9
x3 + X4 + x5 = 5*0.9 - 2*0.75 = 3
(x3 + x4 + x5)/3 = 1
Therefore, the average of assignments x3, x4, x5 must be 100% and the percent increase from 75% to 100% is 25%.

Princeton Review Math Workout for the GMAT 2nd edition, p. 268, #10:

Originally posted by bdennis on 20 Oct 2014, 00:14.
Last edited by Bunuel on 20 Oct 2014, 04:29, edited 1 time in total.
Renamed the topic and edited the question.
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1835
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: Torry has submitted 2/5 of his homework assignments, and he received a  [#permalink]

### Show Tags

22 Oct 2014, 03:14
9
1
First 2 assignments, average = 75, so total = 150

Last 3 assignments, let total = 3x

Setting up the equation

$$\frac{150 + 3x}{5} = 90$$

x = 100

To get the resultant average of 90, the last 3 assignment average should be = 100

$$Percentage = \frac{100-75}{75} * 100 = \frac{1}{3} * 100 = 33.33%$$

_________________

Kindly press "+1 Kudos" to appreciate

##### General Discussion
Senior Manager
Joined: 13 Jun 2013
Posts: 277
Re: Torry has submitted 2/5 of his homework assignments, and he received a  [#permalink]

### Show Tags

20 Oct 2014, 02:45
1
bdennis wrote:
Hi, I need some help understanding why my reasoning is wrong for this question from Princeton Review Math Workout for the GMAT 2nd edition, p. 268, #10:

Torry has submitted 2/5 of his homework assignments, and he received an average grade of 75 for those assignments. If he wishes to receive an average grade of 90 for all his homework assignments, the average grade for Torry's remaining homework assignments must be what percent greater than the average grade for the assignments he has already submitted?
a. 15%
b. 20%
c. 25%
d. 33 1/3%
e. 40%

My faulty solution:
First two HW assignments: x1 + x2 = 2*0.75
Wish five HW assignments: (x1 + x2) + (x3 + x4 + x5) = 5*0.9
2*0.75 + (x3 + x4 + x5) = 5*0.9
x3 + X4 + x5 = 5*0.9 - 2*0.75 = 3
(x3 + x4 + x5)/3 = 1
Therefore, the average of assignments x3, x4, x5 must be 100% and the percent increase from 75% to 100% is 25%.

your solution is correct till the last step.

Generally, to find by what percent x is greater than y, we use the following formula:

((x-y)/y)*100--------------------------------1)

now in this we have to find by what percent average of the remaining three tests is greater than the average of the first two test.

so here x=100 and y=75
substituting these values of x and y in the equation 1) we have

(25/75)*100 = 33(1/3)%
Intern
Joined: 20 Jun 2012
Posts: 1
Re: Torry has submitted 2/5 of his homework assignments, and he received a  [#permalink]

### Show Tags

20 Oct 2014, 03:36
1
My solution:

0.4*75 + 0.6x = 90
30 + 0.6x=90
0.6x = 60
x= 100

100/75= 1.3333...

Ans: D
Manager
Joined: 13 Dec 2013
Posts: 161
Location: United States (NY)
GMAT 1: 710 Q46 V41
GMAT 2: 720 Q48 V40
GPA: 4
WE: Consulting (Consulting)
Re: Torry has submitted 2/5 of his homework assignments, and he received a  [#permalink]

### Show Tags

01 May 2017, 20:05
(2*75/5)+(3x/5)=90
x=100
(25*100)/75=33.3%
Non-Human User
Joined: 09 Sep 2013
Posts: 7781
Re: Torry has submitted 2/5 of his homework assignments, and he received a  [#permalink]

### Show Tags

21 Jul 2018, 07:30
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: Torry has submitted 2/5 of his homework assignments, and he received a &nbs [#permalink] 21 Jul 2018, 07:30
Display posts from previous: Sort by

# Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.