Torry has submitted 2/5 of his homework assignments, and he received an average grade of 75 for those assignments. If

[BTGmoderatorDC]

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%



OA D

Source: Princeton Review

[Scott@TargetTestPrep]

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%

OA D

Source: Princeton Review

We can create the equation:

(2/5)*75 + (3/5)*N = 90

30 + 3N/5 = 90

3N/5 = 60

3N = 300

N = 100

So, the average grade for Torry’s remaining assignments must be 100. As a percentage, the remaining assignments must be:

(100 - 75)/75 x 100 = 25/75 x 100 = 1/3 x 100 = 33 ⅓% greater than the previous assignments.

Answer: D

[deloitte247]

Total assignments = 5
The average grade received in the first 2 assignments = 75
This means the sum of the first 2 assignments = 75 * 2 = 150
Torry wishes to receive an average grade of 90 for all the 5 assignments
This means the sum of the 5 assignments must be at least = 90 * 5 = 450
Total points needed from the remaining 3 = 450 - 150 = 300, this will be an average of 300/3 = 100 points per assignment

Torry's present average = 75
So, Torry is short of 100 - 75 = 25 points i.e he will need 25 more points on the average of the remaining 3 assignments
% needed on the remaining assignments = $$\frac{25}{75}\cdot\frac{100}{1}=33.3\%\ or\ 33\frac{1}{3}\%$$

The average grade for Torry's remaining assignments must be 33.3% greater than the average grade for the assignment he has already submitted.

Answer = D