Answers

2015-12-22T12:35:19+05:30
Let the son complete work in x days . => work done by son in 1 day = 1/x

=> Father completes half work in 3x/4 days
=> He completes full work ( 1/2 work + 1/2work ) in 2 *3x/4 = 3x/2 days
=> Work done by father in 1 day = 1/ ( 3x/2 ) = 2/3x

Now

They take 18 days to complete = 1 work

=> 18 * ( work done by pa + work done by son in 1 day ) = 1

=> 18 * ( 1/x + 2/3x ) = 1

=> 18 ( 1 + 2 / 3 ) = x ( multiply by x on both sides )

=> 18 ( 5/3 ) = x

=> x = 6 * 5 = 30 days .
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