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Work Problem - Machines

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Manager
Joined: 05 May 2005
Posts: 78

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16 May 2007, 18:26
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

How would you solve?

Machine A, working alone at a constant rate, can complete a certain production lot in x hours. Machine B, working alone at a constant rate, can complete 1/5 of the same production lot in y hours. Machines A and B, working together, can complete 1/2 of the same production lot in z hours. What is the value of y in terms of x and z?

a)
5x-10z
2xz

b)
2xz
5x-10z

c)
5xz
x+z

d)
xz
x+z

e)
xz
x+2z
Manager
Joined: 02 May 2007
Posts: 152
Re: Work Problem - Machines [#permalink]

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16 May 2007, 18:32
above720 wrote:
How would you solve?

Machine A, working alone at a constant rate, can complete a certain production lot in x hours. Machine B, working alone at a constant rate, can complete 1/5 of the same production lot in y hours. Machines A and B, working together, can complete 1/2 of the same production lot in z hours. What is the value of y in terms of x and z?

a)
5x-10z
2xz

b)
2xz
5x-10z

c)
5xz
x+z

d)
xz
x+z

e)
xz
x+2z

(B) it is

1/x + 1/5y = 1/2z
=> (5y + x)/5xy = 1/2z
=> 10yz + 2xz = 5xy

=> y = 2xz/(5x - 10z)
Re: Work Problem - Machines   [#permalink] 16 May 2007, 18:32
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