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3 years ago

7

S a punishment for something naughty that we did, my little brother and I have to whitewash both sides of a fence. We start at t

he same time, and we each work at a constant rate.
If we each whitewash one side, I'll finish in 2 hours and my brother will finish in 3 hours. But I'm a nice kid, so after I finish my side, I go around to the other side and help my brother finish his side. From the time I start helping him, how many minutes does it take us to finish the job?

Hint(s):

How many sides per hour can I paint? How about my brother? How about both of us together?

1 answer:

Step2247 [10]3 years ago

8 0

Two and a half hours.

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On rationalizing the denominator, we get

$\rm \: = \: \dfrac{- \sqrt{3} + \sqrt{2} + \sqrt{5}}{2 \sqrt{6}} \times \dfrac{ \sqrt{6} }{ \sqrt{6} }$

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<h3><u>More Identities to </u><u>know:</u></h3>

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