Posted by Trista on Wednesday, November 7, 2012 at 6:20pm.
I no the answer is 6.68. I can't remember how to get this.
work with the amount of job done in one hour. In one hour,
John does 1/11
DeShawn does 1/17
together, they do 1/11 + 1/17 = 28/187
so, to do the whole job, they need 187/28 = 6.68
In general, if there are several people taking a,b,c,... hours to do the job, then working together they can do the job in N hours, where
1/N = 1/a + 1/b + 1/c + ...
Related Questions
math - Amy can clean the house in 7 hours. When she works together with Tom, the...
algebra - A homeowner wishes to insulate her attic with fiberglass insulation to...
Algebra - A homeowner wishes to insulate her attic with fiberglass insulation ...
MATH - 3 boys or 5 girls can clean a compound in 8 hours. in how many hours will...
math - 3 boys or 5 girls can clean a compound in 8 hours. in how many hours will...
math - 3 boys or 5 girls can clean a compound in 8 hours. in how many hours will...
math - 3 boys or 5 girls can clean a compound in 8 hours. in how many hours will...
Math - Stephanie can clean a pool in 1 hour , and Mark can clean the same pool ...
Algebra - -Alfonso can write 100 practice problems for the math team in 20 ...
algebra - A homeowner wishes to insulate her attic with fiberglass insulation to...
For Further Reading
