Problema Solution
Jenny
can cut and split a cord of firewood in 3
fewer hr(s) than Steve
can. When they work together, it takes them 2
hr(s). How long would it take each of them to do the job alone?
Answer provided by our tutors
Let
x = the number of hours Steve needs to do the job alone, x>0
1/x = the rate of Steve per hour
x - 3 = the number of hours Jenny needs to do the job alone and x - 3 > 0 that is x > 3.
1/(x - 3) = the rate of Jenny per hour
1/2 per hour is the together rate
Now we can write:
1/x + 1/(x - 3) = 1/2
........
click here to see the equation solved for x
........
x = 6 hr
We need to ignore the solution x = 1 since x > 3
6 - 3 = 3 hr
Steve needs 6 hours to finish the job alone.
Jenny needs 3 hours to finish the job alone.