A washing machine takes 35 minutes to wash one load of laundry, and in

Question

A washing machine takes 35 minutes to wash one load of laundry, and in between washing different loads of laundry it takes Derek 2 minutes to unload and another 4 minutes to reload the machine. If the washing machine begins washing one load of laundry at 12:30pm, how many loads of laundry can Derek wash and unload before 6:35pm?

(A) 8
(B) 9
(C) 10
(D) 14
(E) 15

(A) 8 
(B) 9 
(C) 10 
(D) 14 
(E) 15

D3N0 · Answer

Ans: B
as per question 4 Minuts to reload + 35 minuts to wash + 2 min to unload = 41 minuts for a set.
time duration 12:30 to 06:35 = 6*60+5 = 365 minutes.
Edited: after correction from  EgmatQuantExpert

total number of sets = 41*8= 328 so remaining 37 minutes.
As machine was already loaded so wash and unload =35+2 =37 minutes so one more round possible.

total rounds = 8+1 = 9

ANS: B

EgmatQuantExpert · Answer

Solution

Given:  
 • Washing machine takes 35 minutes to wash one load of laundry
• Derek takes 2 minutes to unload, and another 4 minutes to reload laundry in between

To find:  
 • The number of loads of laundry Derek can was and unload before 6:35 pm, if the machine started at 12:30 pm

Approach and Working:   
 • To complete one full cycle of load, wash and unload, the time taken = 2 + 35 + 4 = 41 minutes
• The time between 12:30 pm and 6:35 pm = 365 minutes

In that 365 minutes, Derek can complete 8 full cycles in 41 * 8 = 328 minutes
 • Time left = 365 – 328 = 37 minutes

In that 37 minutes, Derek can wash and unload (35 + 2) the last loaded laundry

Therefore, he can wash and unload a total of 9 loads of laundry

Hence, the correct answer is option B.

Answer: B

D3N0 · Answer

sequence will be load + wash + unload = 2+35 + 4 =41
as you mentioned 41*8 = 328 minuts till last unloading. now machine is empty 37 minuts remaining so from here= load 2 min + wash 35 minutes= 37 minutes over but he is not able to unload .. this can not be counted as full cycle..

only 8 rounds are possible.

OR

IS the question saying that first load was already there and that first loading time is not to be included.
Is it the case??
Please clarify..

EgmatQuantExpert · Answer

The question mentions that " ...the washing machine   begins washing   one load of laundry at 12:30pm... "

Hero8888 · Answer

Hi  dkumar2012

You include extra 4 minutes for the last reloading, indeed the last 9th will be shorter - 37 min instead of 41, because you don't need to reload for the next one. (10th)

Tuanguyen248 · Answer

let's say no of washing time is x => the other things to do will be: (x-1) time

So we got the math: 35x+6(x-1) = 6*60 +5 = 365 => x = 9.04 => Answer is B

KSBGC · Answer

Note : In last cycle we will need only 37 mins as in last slot we don't need to reload the machine. ******.

Total time taken to complete each cycle = 35 + 2 + 4 = 41 mins.

Total allocated time = 12.30 to 6 .35 = 365 mins .....................12.30-1-2-3-4-5-6.35 = 6 hrs 5 mins =365 mins

( 365 - 37 ) = 328 = 41* 8 ..........Upon deducting the last cycle we will have complete 8 cycles. We have to add the last cycle to total 8 cycles.

See we can complete total ( 8 + 1 ) = 9 cycles.

Thus the best answer is B.

JeffTargetTestPrep · Answer

We need to determine how many loads can be washed in 6 hours and 5 minutes = 6 x 60 + 5 = 365 minutes. Since each load of laundry is 35 + 2 + 4 = 41 minutes (including unloading and reloading), in 365 minutes, we can do 365/41 ≈ 9 loads.

If we can do exactly 9 loads of laundry before 6:35 pm, let’s ignore the first load for now since it doesn’t need to be reloaded. Let’s count the reload plus wash plus unload time as one load of laundry for each of the remaining 8 loads; then it will take 41 x 8 = 328 minutes for these 8 loads, and we have 365 - 328 = 37 minutes for the first load of laundry. Since the first load requires the wash plus unload time, or 35 + 2 = 37 minutes, this perfectly fits the 37 minutes needed for the first load. Therefore, we can do 9 loads of laundry before 6:35pm.

Answer: B

GyMrAT · Answer

Given Washing M/c wash time = 35 mins

Unload laundry time = 2 mins

Reload laundry time = 4 mins.

So each load, wash & unload cycle is of (35 + 2 + 4) = 41 mins

Washing M/c begins washing first load at 12:30 pm, & the final unload is to happen before 6:35 pm, hence the time available = 6 hrs 5 mins = 365 mins

For the first load, we need to consider only Wash & unload times = 35 + 2 = 37 mins.

Hence time left for subsequent cycles = 365 - 37 = 328 mins.

# of load that can be washed in 328 mins = 328/41 = 8 loads

Total # of loads that can be washed = 9 loads

Answer B.

Thanks,
GyM

proddnav · Answer

In this three different activities are done in a loop

Loading, Washing and Unloading

The Washing Machine Runs from 12:30PM-6:35 PM= 6 hours + 5 minutes= 365 Min

However, the important thing to note here is the first load which begins at 12:30 has already been loaded so the loading time of 4 min is already finished. Hence adding 4+365 min= 369 Min which is the total time

Total time for Loading, washing & unloading is 4+35+2= 41 minutes

369/41= 9

Hence B 9 loads

kabirgandhi · Answer

Since the machine   begins   washing at 12:30, we know this load is already in the machine.

For Load 2 - it will take 2 mins to unload the previous load + 4 mins to reload + 35 mins to wash = 41 mins total, for each load after load 1.

Now our time is 365 minutes (6h + 5m). The first load will take 35 mins to wash, which means we are done with 1 load, and left with 330 minutes for each subsequent load.

Now we can do 330/41 to determine how many loads of laundry we can do in the remaining time, my approximate answer was 8.2, and we add the initial 1 already done, makes it a total of 9.2 loads. Since a load can be completely done or not done, we take 9.

GMATNinja ,  KarishmaB ,  MartyMurray  - is this method good?

MartyMurray · Answer

Your approach is pretty cool, and what you did is close to correct. However, you missed one little thing.

For each load after the first, you included "2 mins to unload the previous load + 4 mins to reload + 35 mins to wash."

Notice that the question is "how many loads of laundry can Derek wash and  unload  before 6:35pm?"

So, he has to unload the last load as well, taking an additional 2 minutes.

So, the correct calculation would be (330 - 2)/41 = 328/41 = 8.

A washing machine takes 35 minutes to wash one load of laundry, and in

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 washing machine takes 35 minutes to wash one load of laundry, and in

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