Kentsidn
Answered

IDNStudy.com, ang iyong mapagkakatiwalaang mapagkukunan para sa eksaktong at maaasahang mga sagot. Hanapin ang impormasyon na kailangan mo nang mabilis at madali sa pamamagitan ng aming komprehensibo at eksaktong platform ng tanong at sagot.

Working together, two servicemen can clean a swimming pool in 6 hours. If both of them worked together for the first 3 hours, and the first stopped for one reason or another, it will require the second 4 hours more to rub clean pool. How long would it take each of them separately to do the job?

Give the complete solution. Thank You.


Sagot :

Let the time needed for the first one to do the job alone be x and for the second be y.

This would mean that their rates would be 1/x and 1/y.

1 / (1/x+1/y) = 6
1 / (x+y/xy) = 6
xy/(x+y) = 6
xy = 6x + 6y

3 ((x+y)/xy) + 4 (1/y) =  1
(3x + 3y + 4x)/xy = 1
7x + 3y = xy

6x + 6y = 7x + 3y
3y = x

xy = 6x + 6y
xy = 6(x+y)
xy = 6(3y+y)
xy = 24y
x = 24

y = 8

Therefore it would take 24 hours for the first person to work alone and 8 hours for the second.