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# It takes 4 cooks 4 hours to bake 4 cakes.

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Intern
Joined: 04 Sep 2017
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It takes 4 cooks 4 hours to bake 4 cakes. [#permalink]

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11 Sep 2017, 04:53
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Difficulty:

45% (medium)

Question Stats:

59% (00:42) correct 41% (00:46) wrong based on 17 sessions

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It takes 4 cooks 4 hours to bake 4 cakes. Assuming no change of rate, how many hours will it take 8 cooks to bake 8 cakes?

I really can't solve this problem. I am having problem in approach.
Every time I see work problems I am stuck in approach.

In this question, I was approaching like
$$\frac{1}{4*4*4}$$

calculating the cakes baked by 1 cook in 1 hour. I don't even know if I am right.
but now I am stuck can anyone help me.
[Reveal] Spoiler: OA

Kudos [?]: 0 [0], given: 1

Math Expert
Joined: 02 Sep 2009
Posts: 41892

Kudos [?]: 128888 [1], given: 12183

Re: It takes 4 cooks 4 hours to bake 4 cakes. [#permalink]

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11 Sep 2017, 08:01
1
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Expert's post
vishuboy wrote:
It takes 4 cooks 4 hours to bake 4 cakes. Assuming no change of rate, how many hours will it take 8 cooks to bake 8 cakes?

I really can't solve this problem. I am having problem in approach.
Every time I see work problems I am stuck in approach.

In this question, I was approaching like
$$\frac{1}{4*4*4}$$

calculating the cakes baked by 1 cook in 1 hour. I don't even know if I am right.
but now I am stuck can anyone help me.

4 cooks take 4 hours to bake 4 cakes;
4*2 = 8 cooks will take 4/2 = 2 hours to bake 4 cakes;
8 cooks will take 2*2 = 4 hours to bake 4*2 = 8 cakes.

Or simply twice as many cooks will make twice as many cakes in the same amount of time.

17. Work/Rate Problems

For more check:
ALL YOU NEED FOR QUANT ! ! !
Ultimate GMAT Quantitative Megathread

Hope it helps.
_________________

Kudos [?]: 128888 [1], given: 12183

Director
Joined: 22 May 2016
Posts: 813

Kudos [?]: 264 [2], given: 551

It takes 4 cooks 4 hours to bake 4 cakes. [#permalink]

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11 Sep 2017, 10:25
2
KUDOS
vishuboy wrote:
It takes 4 cooks 4 hours to bake 4 cakes. Assumingno change of rate, how many hours will it take 8 cooks to bake 8 cakes?

I really can't solve this problem. I am having problem in approach.
Every time I see work problems I am stuck in approach.

In this question, I was approaching like
$$\frac{1}{4*4*4}$$

calculating the cakes baked by 1 cook in 1 hour. I don't even know if I am right.
but now I am stuck can anyone help me.

Attachment:

WRTvariation.png [ 17.23 KiB | Viewed 763 times ]

The resources Bunuel listed are very helpful.

I don't know exactly where you are lost. (No, you are not correct about individual rate, but you are very close!)

There is one basic approach that might help.

Use the standard RT=W formula, but add "number of workers" (or machines, etc.) to the left hand side of that formula.

See the table above. It is a standard RTW table, but one column has been added: # of workers.

We can manipulate RT=W. We can manipulate, exactly the same way, #*R*T = W

First we need individual rate at which the bakers work, i.e. how many cakes per hour does an individual baker make?

We get that rate from the first scenario. Then we use that rate to solve the second scenario.

1. Find individual rate from first scenario

Manipulate the equation from above (# of workers) * r * t = W
# of workers = 4
Rate = ??
Time = 4
Work = 4

Plugging into the formula: 4 * Rate * 4 = 4
Rate = $$\frac{4}{(4 * 4)}$$ = $$\frac{1}{4}$$

(The rate is in cakes/hour. )

2. Use that individual baker rate, and manipulate the equation again for the second scenario. This time you need to find time.

Basic equation once more is (# of workers) * r * t = W
rate of individual worker =$$\frac{1}{4}$$
# of workers = 8
Work = 8

Plugging into equation:

$$8 * \frac{1}{4} * time = 8$$

$$(\frac{8}{4})(Time) = 8$$

$$2*(Time) = 8$$

Time = 4 hours

Hope that helps.

Kudos [?]: 264 [2], given: 551

Intern
Joined: 05 Feb 2017
Posts: 26

Kudos [?]: 9 [1], given: 49

Re: It takes 4 cooks 4 hours to bake 4 cakes. [#permalink]

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11 Sep 2017, 12:06
1
KUDOS
genxer123 wrote:
vishuboy wrote:
It takes 4 cooks 4 hours to bake 4 cakes. Assumingno change of rate, how many hours will it take 8 cooks to bake 8 cakes?

I really can't solve this problem. I am having problem in approach.
Every time I see work problems I am stuck in approach.

In this question, I was approaching like
$$\frac{1}{4*4*4}$$

calculating the cakes baked by 1 cook in 1 hour. I don't even know if I am right.
but now I am stuck can anyone help me.

Attachment:
WRTvariation.png

The resources Bunuel listed are very helpful.

I don't know exactly where you are lost. (No, you are not correct about individual rate, but you are very close!)

There is one basic approach that might help.

Use the standard RT=W formula, but add "number of workers" (or machines, etc.) to the left hand side of that formula.

See the table above. It is a standard RTW table, but one column has been added: # of workers.

We can manipulate RT=W. We can manipulate, exactly the same way, #*R*T = W

First we need individual rate at which the bakers work, i.e. how many cakes per hour does an individual baker make?

We get that rate from the first scenario. Then we use that rate to solve the second scenario.

1. Find individual rate from first scenario

Manipulate the equation from above (# of workers) * r * t = W
# of workers = 4
Rate = ??
Time = 4
Work = 4

Plugging into the formula: 4 * Rate * 4 = 4
Rate = $$\frac{4}{(4 * 4)}$$ = $$\frac{1}{4}$$

(The rate is in cakes/hour. )

2. Use that individual baker rate, and manipulate the equation again for the second scenario. This time you need to find time.

Basic equation once more is (# of workers) * r * t = W
rate of individual worker =$$\frac{1}{4}$$
# of workers = 8
Work = 8

Plugging into equation:

$$8 * \frac{1}{4} * time = 8$$

$$(\frac{8}{4})(Time) = 8$$

$$2*(Time) = 8$$

Time = 4 hours

Hope that helps.

One word:- AWESOME

Kudos [?]: 9 [1], given: 49

Intern
Joined: 13 Sep 2016
Posts: 6

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Re: It takes 4 cooks 4 hours to bake 4 cakes. [#permalink]

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11 Sep 2017, 12:14
It takes 16 man-hours(4 cooks x 4 hours) for 4 cakes
So, it takes 16/4 man-hours for 1 cake

Now to make 8 cakes, we would need 8x4=32 man-hours
We already have 8 cooks with us, and so the number of hours these 8 cooks would need is 32/8=4 hours

Sent from my Redmi Note 3 using GMAT Club Forum mobile app

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Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
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Re: It takes 4 cooks 4 hours to bake 4 cakes. [#permalink]

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14 Sep 2017, 10:35
vishuboy wrote:
It takes 4 cooks 4 hours to bake 4 cakes. Assuming no change of rate, how many hours will it take 8 cooks to bake 8 cakes?

The rate of 4 cooks is 1 cake per hour. We can use a proportion to determine the rate of 8 cooks.

1/4 = x/8

x = 2

Since rate of 8 cooks is 2 cakes per hour, it will take 8/2 = 4 hours to bake 8 cakes.
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Kudos [?]: 836 [0], given: 5

Intern
Joined: 10 Sep 2017
Posts: 9

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Concentration: Operations, Organizational Behavior
Re: It takes 4 cooks 4 hours to bake 4 cakes. [#permalink]

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06 Oct 2017, 12:00
The time will remain the same.
time taken by one cook to bake one cake is 4 hours
4 cooks to bake 4 cakes = 4 hours
8 cooks to bake 8 cakes = 4 hours

as the rate of a single cook is one cake in 4 hours.

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Re: It takes 4 cooks 4 hours to bake 4 cakes.   [#permalink] 06 Oct 2017, 12:00
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# It takes 4 cooks 4 hours to bake 4 cakes.

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