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5 drill machines can drill 15 meters in 5 hours.

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Manager
Joined: 22 Apr 2017
Posts: 120
Location: India
GMAT 1: 620 Q46 V30
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5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 07:17
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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
Intern
Joined: 10 Aug 2017
Posts: 8
Re: 5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 07:27
Mac 5 meters 15 hours 5
Mac x meters 60 hours 2
Do it with proportion.
X/5= 60/15 * 5/2
X=50

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Joined: 02 Aug 2009
Posts: 5733
Re: 5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 07:32
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
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5 drill machines can drill 15 meters in 5 hours. [#permalink]

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06 Nov 2017, 09:17
1
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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

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

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

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12 Nov 2017, 08:47
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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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Re: 5 drill machines can drill 15 meters in 5 hours.   [#permalink] 12 Nov 2017, 08:47
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