Question

A can have a piece of work done in 8 days, b can work three times faster than the a, c can work five times faster than

a. How many days will they take to do the work together ? (a) 3 days (b) 8/9 days (c) 4 days (d) can,t say ans: b

Answer 1

(b) 8/9 days

A will do 1/8 part of the work in 1 day

Similarly, B →3/8

C →5/8

A+B+C→1/8+3/8+5/8=9/8 part of work in 1 day.

Take the reciprocal to get the number of days to complete the whole work, 8/9 days.

Answer 2

Answer:

8/9

Step-by-step explanation:

A's work = 1/8

B's work = 3 times of A = 3A

              = 3 * ( 1 / 8 )     = 3/8

similarly,

C's work = 5 times of A = 5A

               = 5 * ( 1 / 8 )     = 5/8

total days = ?

total work for one day = 1 /8 + 3/8 + 5/8

                                     = 9/8

work for n days = n*(1 day work)

                        1 = n*(9 / 8)

     Therefore, n = 8 / 9