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

Question

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%

This is a  PS Butler Question

Check the links to other Butler Projects:

Data Sufficiency Butler  
  Critical Reasoning Butler  
  Reading Comprehension Butler  
  Data Insights Butler

ankushsambare · Answer

Let x be the average grade for Torry's remaining homework assignments
Using Alligation:
(x-90)/(90-75) = 2/3
on solving for x, we get x = 100
And we know that 100 is 33.33% greater than 75
Hence,  D

ravi1522 · Answer

Hello ,
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
Lets assume there are 5 assignments
To get average 90 
lets assume new score as s
2x75+(3xs)=5x90
s=100
% =((100-75)/75 )*100
33.33 %

Hence option D is correct

Dereno · Answer

Let the number of Homework HW assignments be 5.

For two of the HW assignments, the average is 75

We need to find the average of the remaining (3) HW assignments.

The total average for the HW assignments be 90.

Using mixtures and allegations

75 —————- 90 —————— x

2 : 3

90-75 = 15

x - 90 = ?

15 / (x-90) = (3/2)

15*2 = 3*(x-90)

10 = (x-90)

x =100

The percentage increase from 75 = ?

= (100-75) / 75

= 25/75

= (1/3)

33 1/3 %

Option D

harjas2222 · Answer

Can you please explain the Alligation method or send a link please? sorry for the trouble

Bunuel · Answer

Mixture Problems

Theory: 
 
  Weighted Average and Mixture Problems on the GMAT  
  Tips and Tricks: Mixtures

Questions: 
 
  DS Questions  
  PS Questions

For more check  Ultimate GMAT Quantitative Megathread

lkj123 · Answer

let assume total work = 5 unit
already completed = 2/5*5 that is 2 unit
remaining unit = 3
point in already completed work= 75
he want overall avg =90
apply weighted avg formula

(2*75)+(3*x)/5

x=100

% change above 75 is =25/75*100 = 33.33%
option D

dhairya18 · Answer

You can think of it in terms of total points using a 2x and 3x split for the assignments.

If we let the total number of assignments be 5x, the total points needed for a 90 average is 450x. Since Torry already finished 2x assignments with an average of 75, he has earned 150x points so far. This leaves 300x points needed for the remaining 3x assignments.

To find the average for those remaining assignments, we just divide 300x by 3x, which gives us 100. Comparing this to his original average of 75, the increase is 25 points. Since 25/75 simplifies to 1/3, the average must be 33 1/3% greater.

Answer: D

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

Prep Toolkit

Top 5 GMAT Debrief Videos

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

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

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

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

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards