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

 It is currently 16 Jan 2019, 00:44

### 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

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### The winning strategy for a high GRE score

January 17, 2019

January 17, 2019

08:00 AM PST

09:00 AM PST

Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
• ### Free GMAT Strategy Webinar

January 19, 2019

January 19, 2019

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# A student is trying to achieve an overall average of at least 90.0 to

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 52122
A student is trying to achieve an overall average of at least 90.0 to  [#permalink]

### Show Tags

18 Apr 2018, 17:25
00:00

Difficulty:

55% (hard)

Question Stats:

68% (02:06) correct 32% (03:20) wrong based on 32 sessions

### HideShow timer Statistics

A student is trying to achieve an overall average of at least 90.0 to earn a grade of A in a college course. In determining the overall average for the course grade, the instructor calculates a weighted average based on the four major, 100-point exams in the course. The mean (arithmetic average) of the scores on the first three exams counts as 60 percent of the overall average, and the fourth (and final) exam counts as 40 percent of the overall average. The student has scores of 80, 95, and 92 on the first three major exams. Which of the following scores on the fourth major exam would result in an overall average that would earn the student an A in the course?

I. 90
II. 91
III. 92

(A) I only
(B) II only
(C) III only
(D) II and III only
(E) I, II, and III

_________________
Senior SC Moderator
Joined: 22 May 2016
Posts: 2329
A student is trying to achieve an overall average of at least 90.0 to  [#permalink]

### Show Tags

18 Apr 2018, 18:54
1
1
Bunuel wrote:
A student is trying to achieve an overall average of at least 90.0 to earn a grade of A in a college course. In determining the overall average for the course grade, the instructor calculates a weighted average based on the four major, 100-point exams in the course. The mean (arithmetic average) of the scores on the first three exams counts as 60 percent of the overall average, and the fourth (and final) exam counts as 40 percent of the overall average. The student has scores of 80, 95, and 92 on the first three major exams. Which of the following scores on the fourth major exam would result in an overall average that would earn the student an A in the course?

I. 90
II. 91
III. 92

(A) I only
(B) II only
(C) III only
(D) II and III only
(E) I, II, and III

There are a lot of ways to do the problem. One approach: straightforward weighted average.

Weighted average equation is
(Mean of first 3 tests)*(.60) PLUS
(Final exam score) * (.40) =
Overall Average

The mean score of first three exams counts for 60% of the whole grade.

1) Find the mean of the the first three exams

$$\frac{80+92+95}{3}=\frac{267}{3}=89$$

2) Multiply by .6 to get the actual number of points he has so far: $$(89 * .6) = 53.4$$

3) Desired overall average is 90. Points needed? He has 53.4

$$(90 - 53.4) = 36.6$$ points needed

That is, to earn a 90 overall, the product of
(final exam score) * (.4) must be $$\geq 36.6$$

4) Check Options
Multiply each option's score by (.4) to find the actual point value. He needs 36.6 points

Final exam score of
I. 90. NO
Mental math: $$(90*.4) = 36$$

II. 91 ALSO NO
$$91= 90 + 1$$
$$(90 * .4) = 36$$
$$(1 * .4) = .4$$
$$36 + .4 = 36.4$$

If you're short on time, mark C and move on. Options I and II do not work.

III. 92 - YES
$$92 * 4 = 36.8$$

He needed 36.6 to get an overall average of at least 90. With a final score of 92, he made it:
$$36.8 + 53.4 = 90.2$$

_________________

Never look down on anybody unless you're helping them up.
--Jesse Jackson

A student is trying to achieve an overall average of at least 90.0 to &nbs [#permalink] 18 Apr 2018, 18:54
Display posts from previous: Sort by