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If brian paint a fence in 4 hours and Scott can paint the same fence in 6 hours, how long will it take when the two of them work together?

A. 2 hours and 24 minutes
B. 3 hours and 12 minutes
C. 3 hours and 44 minutes
D. 4 hours and 10 minutes
E. 4 hours and 33 minutes

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Eduard22sly

Answer: option A. 2 hours 24 minutes

Step-by-step explanation:please see attachment for explanation

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Answer:

2.40 hours   or 2 hours and 40 minutes

Step-by-step explanation:

If Brian paint a fence in 4 hours, then Brian would paint 1/4 of a fence in 1 hour

And if Scott paint the fence in 6 hours then Scott would do 1/6 of the fence in 1 hour.

Then These two fellows wil pain in 1 hour time

1/4  +  1/6    =   ( 3 + 2 ) / 12    =  5 / 12

Then by rule of three and taken into account that 12/12  is the unit we can express:

If both guys paint  5/12 of the fence in 1 hour how long would they take to paint the missing part  ( 7/12 ), and add one hour to get the final result

 1  hour       ⇒   5/12

   x ??          ⇒    7/12

Then     x  =  ( 7 / 12)  /  ( 5 /12)    ⇒     x  = 7/5  hours

x =  1.40   or   1 hour and 40 minutes

Then to paint the whole fence Brian and Scott will take 2.40 hours

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