Noah and Sarah can finish apiece of work in 10 days. Noah can do the job himself in twelve days. If Sarah wanted to do the job alone, how long would it take her?
2006-10-19 18:56:34 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
10(n+s)=12n
10s=2n
n=5s
12n=12(5s)=60s
The job will take Sarah 60 hours.
2006-10-19 19:02:01 · answer #1 · answered by Scott K 2 · 2⤊ 0⤋
Tutoronline is correct. If Noah can do the job in 12 days, that means he can do 1/12 th of the job in 1 day. So therefore in 10 days, he can do 10/12 ths of the job. Thus if they both did the job in 10 days, Sarah must have done the other 2/12 ths of the job (10/12 ths of a job + 2/12 ths of a job = 1 job). For Sarah, if 2/12 ths of a job = 10 days, then multiply through by 6 to get 1 job = 60 days.
2006-10-20 07:56:59 · answer #2 · answered by falzoon 7 · 0⤊ 0⤋
Why would Sarah take only 60 hours Scott?? She would take minimum 60 days and I wonder if she could do the job on her own anyway if she is so much slower than Noah. RT is right teamwork is the key here..
2006-10-20 04:38:10 · answer #3 · answered by Anonymous · 0⤊ 0⤋
in ten days, 10/12 of the work is done.
Hence Sarah did 2/12 work in ten days or
need 6 x 10 = 60 days to complete it.
2006-10-20 02:05:54 · answer #4 · answered by tutoronline 1 · 0⤊ 1⤋
based on math and theory, Scott K are right.
But based on pratical it might not be. have you ever heard that one house can pull 6 tons, what if two horses are pulling together? not 6 tons x 2 = 12 tons. the correct answer is two horses can pull more than 24 tons!. that is power of the teamwork!
2006-10-20 02:08:06 · answer #5 · answered by RT 3 · 0⤊ 0⤋