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Three hoses, x, y, and z, each pump water at a constant rate. How long

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Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 17 Mar 2017, 03:06
1
2
00:00
A
B
C
D
E

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Question Stats:

78% (00:44) correct 22% (01:14) wrong based on 130 sessions

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Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post Updated on: 17 Mar 2017, 11:23
Bunuel wrote:
Three hoses, x, y, and z, each pump water at a constant rate. How long will it take the hoses to fill up a 30,000-gallon tank?

(1) Hoses x and z each pump water at constant rate of 120 gallons per hour.
(2) Hose y pumps water at half the rate of x.



(1) no info for rate of y
insuff

(2) clear insuff

combining let they take time t hrs then
1/x+1/z+1/2x = 30000/t

where z & x have each 120g / h of rate
thus y have 60 g / hr of rate
thus combining we get all three rates
suff

Ans C

Originally posted by rohit8865 on 17 Mar 2017, 07:52.
Last edited by rohit8865 on 17 Mar 2017, 11:23, edited 1 time in total.
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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 17 Mar 2017, 09:18
Why not C it says each pump so we know value of X
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Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post Updated on: 17 Mar 2017, 11:24
vivek2k70 wrote:
Why not C it says each pump so we know value of X



yes u are correct

Ans must be C

Originally posted by rohit8865 on 17 Mar 2017, 09:20.
Last edited by rohit8865 on 17 Mar 2017, 11:24, edited 1 time in total.
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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 17 Mar 2017, 09:22
1) You have no information on Y, so insufficient
2) You have no information on Z, so insufficient

Combining 1 & 2 still insufficient because we do not know the constant rate of x or z
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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 17 Mar 2017, 11:13
Each statement alone is insufficient. But in (I) its given that each of them ie x and z pumps at 120 gallons/hr. (II) says y pumps half the rate of x which is 60 gallons /hr. Isn't combining both sufficient to find how long it takes to fill the tank ?


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Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 21 Mar 2017, 21:52
I'm not sure about this one. The answer could be C if we can assume that all of the hoses started at the same time. But that is not explicitly stated. So, I think the answer is E.

R x T = W
X 120 g/hr
Y 60 g/hr
Z 120 g/hr

(120+120+60) x T = 30K this can be solved
or
120*t_x + 120*t_z + 60*t_y = 30K this can't be solved
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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 22 Mar 2017, 03:47
Bunuel wrote:
Three hoses, x, y, and z, each pump water at a constant rate. How long will it take the hoses to fill up a 30,000-gallon tank?

(1) Hoses x and z each pump water at constant rate of 120 gallons per hour.
(2) Hose y pumps water at half the rate of x.


We need to know the exact value of flow rate for x, y and z

St 1: flow rate of y not mentioned. INSUFFICIENT

ST 2: relation between x and y is given. but no exact value can be calculated. INSUFFICIENT

St 1 & St 2: y = x/2 and x = 120, z = 120. hence all three is known. SUFFICIENT

Option C
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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 22 Mar 2017, 03:51
C should be the answer.
Combining both statements we will be able to find the answer.

OA plz ??

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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 22 Mar 2017, 03:57
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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 23 Mar 2017, 05:28
Option C

I: No information about pumping rate of hose Y: Insufficient

II: Pumping rate X = 2 * (Pumping rate Y)
No information on pumping rates. Insufficient

I + II: Pumping rate of all three hoses can be obtained. Assuming all three hoses pump for same duration of time (unless stated otherwise), the time required to fill tank of any volume can be estimated.
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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long  [#permalink]

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New post 26 Dec 2017, 10:30
Hi All,

We're told that 3 pumps each pump water at a constant rate. We're asked how long it would take to fill up a 30,000 gallon tank.

If we're meant to assume that the tank starts off 'empty', then this is a relatively straight-forward prompt (we need the rates of the 3 pumps to answer the question).

1) Hoses X and Z each pump water at constant rate of 120 gallons per hour.

This Fact tells us nothing about the rate of Hose Y, so the answer will vary depending on that rate.
Fact 1 is INSUFFICIENT

2) Hose Y pumps water at half the rate of X.

This Fact tells us nothing about any of the rates, so the answer will vary depending on those rates.
Fact 2 is INSUFFICIENT

Combined, we know....
Hose X = 120 gallons/hour
Hose Z = 120 gallons/hour
Hose Y = 60 gallons/hour

We can now calculate how long it would take to pump 30,000 gallons of water. Again, if we're meant to assume that the tank starts off empty, then this information is SUFFICIENT. IF there's some water in the tank though, then the information is INSUFFICIENT (we would need to know the exact volume of water that needs to be pumped).

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Re: Three hoses, x, y, and z, each pump water at a constant rate. How long   [#permalink] 26 Dec 2017, 10:30
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