Question

if A can do work in 12 hours, B can do same work in 15 hours and C can do the same work in 20 hours. Then how much time will they take to complete the work if they are working together ​

Answer 1

Answer:

5 hours

Step-by-step explanation:

Time taken by A = 12 hours

B = 15 hours

C = 20 hours

by lcm (lcm is 60) we know that

=> A can do 5 unit of work per hour

similarly b = 4 unit and C = 3unit per hour

So total unit of work done by three is

=> 5+4+3 = 12 unit per hous

so

time taken = total work/ work done per hour

=> 60/12 = 5 hours

Answer 2

Answer:

20 hours

Step-by-step explanation:

because if A can do in 12 hours and B can do in 15 and C can do in 20 so A and B will finish their work before C and C will be the last one so they will complete their work in 20hours