A delivery truck starts on its route with a load of goods weighing T

Question

A delivery truck starts on its route with a load of goods weighing T tons. At each of its first 4 stops, 1/2 of the weight of the goods still on the truck is unloaded. After the 4th stop, what is the weight, in tons, of the goods still on the truck?

A. 15T/16

B. T/4

C. T/6

D. T/8

E. T/16

PS21183

A. 15T/16

B. T/4

C. T/6

D. T/8

E. T/16

PS21183

rajjoiitkgp · Answer

After stop 1: T/2
After stop 2: T/4
After stop 3: T/8
After stop 4: T/16

Batman117 · Answer

For such kind of questions we can use formula of 2^n
Where n is number of action.
As we have to identify after 4th unloading
It will be 1/2^4 =1/16

Same if they have asked for after 6th unloading,just put n=6.

Posted from my mobile device

BrentGMATPrepNow · Answer

If half the weight is REMOVED, then half the weight REMAINS

Initially , weight = T (tons)
 After 1 stop : weight remaining = (1/2)T
 After 2 stops : weight remaining = (1/2)(1/2)T
 After 3 stops : weight remaining = (1/2)(1/2)(1/2)T
 After 4 stops : weight remaining = (1/2)(1/2)(1/2)(1/2)T = (1/16)T = T/16

Answer: E

Cheers,
Brent

Abhishek009 · Answer

Let total weight T = 16

Load unloaded on 1st stop is 8 ; Load left = 8
Load unloaded on 2nd stop is 4 ; Load left = 4
Load unloaded on 3rd stop is 2 ; Load left = 2
Load unloaded on 4th stop is 1 ; Load left = 1

Hence, Load left on the truck is  \frac{1}{16} = \frac{T}{16} , Answer must be (E)

Kimberly77 · Answer

Hi  BrentGMATPrepNow , when using number 20 testing, I end up with 20> 10> 5 > 2.5> 1.25/20 ?
Wondering why it only work with 16 only? Could you help? Thanks

BrentGMATPrepNow · Answer

I believe you are using the input-output approach. 
Am I right?

If so, you can use ANY values you want.
If T =  20  (tons), then the answer to our question is  1.25  tons of goods remaining (NOT 1.25/20) .
So now we'll take each answer choice, and INPUT T =  20 , to see if we get an OUTPUT of  1.25

If you do this, you will see that none of the first four options work, but...

E) T/16 =  20 /16 =  1.25 . Perfect!!

DanTheGMATMan · Answer

Just keep it simple and cut in half each time:

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

bumpbot · Answer

Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.

A delivery truck starts on its route with a load of goods weighing T

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

A delivery truck starts on its route with a load of goods weighing T

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