Question

a can do a piece of work in 14 days while B can do in 21 days they begin together but 3 days before the completion of work a leaves off find the total number of days taken to complete the work​

Answer 1

Answer:

12 9/10

Step-by-step explanation:

a can work in 1 days = 1/14 part

B can work in 1 days = 1/21 part

a and B can total work in 1 days

=( 1/14 + 1/21 ) part

= 5/42 part

a and B work together can complete work in

= 42/5 days

= 8 2/5 days

But a and B work together for (8 2/5 - 3 ) days

= 5 2/5 days

= 27/5 days

part of completion work = 5/42 * 27/5

= 9/14 part

remaining part of the work = (1 - 9/14) = 5/14 part

B can complete the remaining 5/14 part of work in

= (5/14 ) / (1/21) = 5/14 * 21

= 15/2 days

Total number of days for complete the work

= 27/5 + 15/2

= ( 54+ 75)/10 days

= 129/10 days

= 12 9/10 days