SOLUTION: 1. Kristen could shovel a large parking lot after a 12" snowfall in 5 hours. It would take Bob 8 hours to shovel the same driveway. How long would it take them if they worked on th

Algebra ->  Rate-of-work-word-problems -> SOLUTION: 1. Kristen could shovel a large parking lot after a 12" snowfall in 5 hours. It would take Bob 8 hours to shovel the same driveway. How long would it take them if they worked on th      Log On


   

Question 85901: 1. Kristen could shovel a large parking lot after a 12" snowfall in 5 hours. It would take Bob 8 hours to shovel the same driveway. How long would it take them if they worked on the jon together? Answer to the nearest minute. If Lisa helps them they can do the lot in one hour. How long would it take Lisa to complete the job?


2. A painting job can be completed by 7 painters in 17 days. If 14 more painters join the team 8 days after starting the job, then how many more days are required to complete the job?
Answer by 303795(602) About Me  (Show Source):
You can put this solution on YOUR website!
Q1. Kirsten does the job in 5 hours so she does 1%2F5 of the job per hour.
Bob does the job in 8 hours so he does 1%2F8 of the job per hour.
Combined they will do 1%2F8+%2B+1%2F5=13%2F40 of the job per hour. The job will therefore take40%2F13hours ie 3 hours and 1%2F13 of an hour or 3 hours and 4.6 minutes.
If Lisa helps the job is done in 1 hour so she must have done 27%2F40 of it. She would therefore take 40%2F27 hours or 1 hour and 13%2F40 of an hour or 1 hour and 19.5 minutes.
Q2. There are 17 x 7 = 119 days of painting to be done in total.
After 8 days they have painted 7 x 8 = 56 days of the job so there will be 119 - 56 = 63 days of painting to go. With a painting team of 21 painters they will take 3 days to paint the last 63 days of work.