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Friday, July 21 2017 @ 03:33 PM CDT
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 Urgent pls help !!
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By: Jlen (offline)  Monday, September 22 2014 @ 08:12 AM CDT (Read 885 times)  
Jlen

Hi all,

Pls help with the below question.

Audrey, Brenda and Cindy wanted to complete a jigsaw puzzle. Audrey and Brenda would take
3 hours to complete the jigsaw puzzle. Cindy and Brenda would take 9 hours while Audrey and Cindy
would take 4 hours to complete the same jigsaw puzzle. How long would it take the 3 girls to complete
The jigsaw puzzle together ?

Ans : 2 22/25 h

Thanks
Regards,
Jaylen

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Registered: 05/05/13
Posts: 10

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By: echeewh (offline)  Monday, September 22 2014 @ 11:33 AM CDT  
echeewh

Hey <Jlen>

Following is my worked solution:

In 1 hour,

A + B = (1/3) -- (1)
C + B = (1/9) -- (2)
A + C = (1/4) -- (3)

(1)+(2)+(3) ... and we have ...

2A + 2B + 2C = (1/3) + (1/9) + (1/4)
2(A + B + C) = (12/36) + (4/36) + (9/36) = (25/36)
A + B + C = (25/36) ÷ 2 = (25/72)

i.e. (25/72) of the puzzle would take 1 hour to complete by the 3 girls.

1 Whole puzzle = (72/72) = 1 ÷ (25/72)
= (72/25)
= 2 22/25 hours

======

Trust this helps.

Do let me know again if there's further clarification.

Cheers,
Edward

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Registered: 04/21/11
Posts: 623

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