Answers

2015-11-25T22:30:16+05:30
Let us take x = Time it will take for both of them

Then,

x(1/10 + 1/15) = 1

x(15 + 10) = 150

x(25) = 150

x = 6 days 

Hope i helped you! :)

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2015-11-26T06:21:20+05:30
work can do by viral=10 days
work can do by raja=15days
efficency of viral= 1/10
efficency of raja=1/15
by adding eifficiency we can get their efficiencies
1/10+1/15= 3+2/30=5/30=1/6
 we have get teir effciency 
 so no of days = 6
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