SOLUTION: 4 people can paint 7 walls in 31 minutes. How many minutes will it take for 10 people to paint 8 walls? i need an explanation how this equals 14 9/35 thanks for your time

Algebra ->  Rate-of-work-word-problems -> SOLUTION: 4 people can paint 7 walls in 31 minutes. How many minutes will it take for 10 people to paint 8 walls? i need an explanation how this equals 14 9/35 thanks for your time       Log On


   



Question 775811: 4 people can paint 7 walls in 31 minutes.
How many minutes will it take for 10 people to paint 8 walls?
i need an explanation how this equals 14 9/35
thanks for your time in advance.

Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
1 job = 1 wall.

Look first at the 4 people doing 7 jobs in 31 minutes. One job would require these four people to only work (1/7) of the 31 minutes. Meaning is:
4 people do 1 job in (1/7)31 minutes.

WHAT is the one-person rate for 1 job? Instead of 4 people and %281%2F7%2931 minutes, this would be 1 person and 4 times more than %281%2F7%2931.
1 person does at the rate of 1%2F%284%2A%281%2F7%2931%29 job per minute.
1 person rate is highlight%287%2F%284%2A31%29%29 job per minute.

The uniform rate basic idea is r*t=j where r = rate of work in jobs per minute, t is the work time in minutes, and j is how much or many jobs. Also, the rates of the same kind of persons doing the work are simply added when they work together, ideally; and multiplication is used to show their count.

Given the one-person rate found, n=10 people to do the work, and j=8 for 8 walls, find t, the number of minutes to paint the 8 walls (the 8 jobs).

highlight%2810%287%2F%284%2A31%29%29%2At=8%29
Solve for t.
t=%288%2A4%2A31%29%2F%2810%2A7%29
t=%2816%2A31%29%2F%2835%29
highlight%28t=496%2F35%29 minutes


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Yes, the whole number part of the quotient IS 14.