Thursday

July 24, 2014

July 24, 2014

Posted by **Anonymous** on Tuesday, January 8, 2013 at 10:32am.

- maths -
**Jennifer**, Wednesday, January 9, 2013 at 7:37pmLet the rate at which A works be a; the rate at which B works be b; the rate at which C work be c:

(a + b)*12 = 1

(b + c)*15 = 1

a = 2*c

gives

b + a/2 = 1/15

b = 1/15 - a/2

Substituting into the first equation:

(a + 1/15 - a/2)*12 = 1

a/2 + 1/15 = 1/12

a/2 = 1/12 - 1/15 = (15-12)/(15*12)

a/2 = 3/(15*12) = 1/(5*12) = 1/60

a = 1/30

The rate at which a works is 1/30 of the work per day; so a will complete the task in 30 days.

**Related Questions**

maths - A and B together can do a piece of work in 12 days; B and C together can...

maths - Please guide me to solve the below problem: 'A'an do 2/3 of a work in 40...

maths - A completes a works in 15 days and B completes the same work in 20 days...

Math - A and B caan finish typing a manuscript in 8/3 days; B and C together, in...

maths ( mental ability) - P can do a piece of work in 9 days. Q is 50% more ...

math - Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2...

math - If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do ...

Math - If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do ...

math - If A can do a job in 6 days that V can do in 5 1/2 days and C can do in 2...

Math(work problem) - A man can do the job in 8 days after 3 days of working a ...