If the average (arithmetic mean) of 5 numbers j, j + 5, 2j – 1, 4j – 2

Question

If the average (arithmetic mean) of 5 numbers j, j + 5, 2j – 1, 4j – 2, and 5j – 1 is 8, what is the value of j ?
 A.  \frac{1}{3} 
B.  \frac{7}{13} 
C. 1
 D. 3
 E. 8

sashiim20 · Accepted Answer

Average of 5 numbers j, j + 5, 2j – 1, 4j – 2, and 5j – 1 is 8

Average = Total (sum of numbers)/ number of terms

[ j + (j+5) + (2j-1) + (4j-2) + (5j-1) ] / 5 = 8
[13j + 1 ] / 5 = 8
13j +1 = 8* 5
13j = 40 - 1 = 39
j = 39/13 = 3 .... Answer D.....

Please, consider giving kudos if you find my answer helpful in any way

Abhishek009 · Answer

j + ( j + 5 ) + ( 2j – 1 ) + ( 4j – 2 ) + ( 5j – 1 ) = 40

Or, 13j + 1 = 40

Or, 13j = 39

Or, j = 3
 
Hence answer will be (D) 3

ScottTargetTestPrep · Answer

We can create the equation:

(j + j + 5 + 2j - 1 + 4j - 2 + 5j - 1)/5 = 8

13j + 1 = 40

13j = 39

j = 3

Answer: D

ScottTargetTestPrep · Answer

We can create the equation:

(j + j + 5 + 2j - 1 + 4j - 2 + 5j - 1)/5 = 8

13j + 1 = 40

13j = 39

j = 3

Answer: D

BrentGMATPrepNow · Answer

GIVEN: he average (arithmetic mean) of 5 numbers  j ,  j + 5 ,  2j – 1 ,  4j – 2 , and  5j – 1  is  8

We can write:  \frac{j + (j+5) + (2j-1) + (4j-2)+ (5j-1)}{5}=8

Multiply both sides of the equation by  5  to get:  j + (j+5) + (2j-1) + (4j-2)+ (5j-1) = 40

Simplify to get:  13j + 1 = 40

Subtract  1  from both sides to get:  13j = 39

Divide both sides by  13  to get:  j = \frac{39}{13}=3

Answer: D

RELATED VIDEO
 https://www.youtube.com/watch?v=Y9f_0QJU1ug

ThatDudeKnows · Answer

Take a look at the answer choices. Most of them look really easy to work with. Maybe we can just use PITA (Plugging in the Answers).
Let's try C. Our numbers are 1, 6, 1, 2, 4. Is the average 8? Nope! Do we need something bigger or smaller? Bigger. 
Okay, let's try D. Our numbers are now 3, 8, 5, 10, and 14. That sure looks close. Do we even really need to add them up and divide by 5, or can we just tell that E is going to be way too big.

Answer choice D.

ThatDudeKnowsPITA

BrushMyQuant · Answer

Given that the Average (arithmetic mean) of 5 numbers j, j + 5, 2j – 1, 4j – 2, and 5j – 1 is 8 and we need to find the value of j

================================================================

Theory
 ‣‣‣ Mean or Average = Sum Of All The Numbers) / (Total Number Of Numbers)

================================================================

Average =  \frac{Sum}{5}  =  \frac{j + (j+5) + (2j-1) + (4j-2) + (5j-1)}{8}  =  \frac{13j + 1}{5}  = 8 (given)

=> 13j + 1 = 5*8 = 40
=> 13j = 40 - 1 = 39
=> j =  \frac{39}{13}  = 3

So,  Answer will be D .
Hope it helps!

Watch the following video to Learn the Basics of Statistics

https://www.youtube.com/watch?v=Cvy_HHw4KIs

Davronjon · Answer

Quick solution:

j+j+2j+4j+5j + 5-1-2-1 =8 *5 =40
13j+1=40
13j=39
j=3

Answer: D

bumpbot · Answer

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.

If the average (arithmetic mean) of 5 numbers j, j + 5, 2j – 1, 4j – 2

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

If the average (arithmetic mean) of 5 numbers j, j + 5, 2j – 1, 4j – 2

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