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# 5 drill machines can drill 15 meters in 5 hours.

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Manager
Joined: 22 Apr 2017
Posts: 76

Kudos [?]: 30 [1], given: 59

Location: India
Schools: MBS '20 (S)
GPA: 3.7
5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 06:17
1
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Difficulty:

25% (medium)

Question Stats:

75% (01:22) correct 25% (01:54) wrong based on 75 sessions

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5 drill machines can drill 15 meters in 5 hours. Assuming the speed of each machine to be the same, how many machines would be needed to drill 60 meters in 2 hours?

A)8
B)16
C)23
D)50
E)60
[Reveal] Spoiler: OA

Kudos [?]: 30 [1], given: 59

Intern
Joined: 10 Aug 2017
Posts: 8

Kudos [?]: 0 [0], given: 2

Re: 5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 06:27
Mac 5 meters 15 hours 5
Mac x meters 60 hours 2
Do it with proportion.
X/5= 60/15 * 5/2
X=50

Sent from my iPhone using GMAT Club Forum

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Math Expert
Joined: 02 Aug 2009
Posts: 5365

Kudos [?]: 6151 [0], given: 121

Re: 5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 06:32
ManishKM1 wrote:
5 drill machines can drill 15 meters in 5 hours. Assuming the speed of each machine to be the same, how many machines would be needed to drill 60 meters in 2 hours?

A)8
B)16
C)23
D)50
E)60

to drill 15 mtr in 5 hrs, 5 machines are required..
so to drill 15*4 mtr in 5 hrs, 5*4 machines are required..
to drill 60 mtr in 1 hrs, 20*5 machines are required..
finally to drill 60 mtr in 2 hrs, 100/2 or 50 machines are required..

D
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

Kudos [?]: 6151 [0], given: 121

VP
Joined: 22 May 2016
Posts: 1137

Kudos [?]: 407 [1], given: 647

5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 08:17
1
KUDOS
ManishKM1 wrote:
5 drill machines can drill 15 meters in 5 hours. Assuming the speed of each machine to be the same, how many machines would be needed to drill 60 meters in 2 hours?

A)8
B)16
C)23
D)50
E)60

Find a machine's individual rate from the first information, and use it to solve the question.

W = (# of machines) * (indiv.) rate * time
W = 15, # of machines = 5, rate = ??, time = 5

15 = 5 * rate * 5
15 = 25 * rate

Individual rate = $$\frac{15}{25}=\frac{3}{5}$$ in meters/hour

At that rate, how many machines are needed to drill 60 meters in 2 hours?

W = (# of machines) * (indiv.) rate * time
W = 60, # of machines = ??, rate = $$\frac{3}{5}$$, time = 2

60 = (# of machines) * $$\frac{3}{5}$$ * 2
60 = (# of machines) * $$\frac{6}{5}$$

# of machines = $$\frac{60}{(\frac{6}{5})}= 60 * \frac{5}{6}=$$ 50

Kudos [?]: 407 [1], given: 647

Target Test Prep Representative
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Re: 5 drill machines can drill 15 meters in 5 hours. [#permalink]

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12 Nov 2017, 07:47
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Expert's post
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This post was
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ManishKM1 wrote:
5 drill machines can drill 15 meters in 5 hours. Assuming the speed of each machine to be the same, how many machines would be needed to drill 60 meters in 2 hours?

A)8
B)16
C)23
D)50
E)60

The rate for 5 drill machines is 15/5 = 3 meters per hour. We need to determine how many drill machines we need for a rate of 60/2 = 30 meters per hour. Since 30 is 10 times 3, we would need 5 x 10 = 50 drill machines.

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Jeffery Miller

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Kudos [?]: 990 [1], given: 5

Re: 5 drill machines can drill 15 meters in 5 hours.   [#permalink] 12 Nov 2017, 07:47
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