Pintu takes 6 days more than those of Nishu to complete certain work. If they work together they finish it in 4 days. How many days would it take to complete the work if they work alone.
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Answered by
5
We have to multiply the no. = 6×4 days = 24 days... plzzzz mark my answer as brain list..
Answered by
29
Let Nishu takes x days to complete the work and Pintu takes (x+6) days
so in 1 day Nishu completes 1/x part of the work
and in 1 day Pintu completes 1/(x+6) part of the work
so they together complete {1/x + 1/(x+6)} part
of the work in 1 day
so they complete the full work in
1/{1/x + 1/(x + 6)} which is equal to 4 as given in question.
so, 1/x + 1/(x+6) = 1/4
( 2x + 6)/(x^2+6x) =1/4
8x + 24 = x^2 + 6x
x^2 - 2x - 24 =0
x^2 - 6x + 4x - 24 =0
x(x - 6) + 4(x - 6) =0
(x -6)(x + 4) =0
so ,x = 6 because x can't be - 4
so Nishu completes in 6 days and Pintu completes in (6+6=) 12 days
so in 1 day Nishu completes 1/x part of the work
and in 1 day Pintu completes 1/(x+6) part of the work
so they together complete {1/x + 1/(x+6)} part
of the work in 1 day
so they complete the full work in
1/{1/x + 1/(x + 6)} which is equal to 4 as given in question.
so, 1/x + 1/(x+6) = 1/4
( 2x + 6)/(x^2+6x) =1/4
8x + 24 = x^2 + 6x
x^2 - 2x - 24 =0
x^2 - 6x + 4x - 24 =0
x(x - 6) + 4(x - 6) =0
(x -6)(x + 4) =0
so ,x = 6 because x can't be - 4
so Nishu completes in 6 days and Pintu completes in (6+6=) 12 days
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