Question

A,B and C can do a piece of work in 15,12 and 20 days respectively. They started the work together but C left after 2 days . In how many days will A and B complete the work
​

Answer 1

Answer:

lcm of 15,12,20=60

60/2=30

Answer 2

Answer:

Work is done by A in one day =  

15

1

​  

 

By B=  

12

1

​  

 

C=  

20

1

​  

 

Together in 1 Day =  

15

1

​  

+  

12

1

​  

+  

20

1

​  

=  

60

4+5+3

​  

=  

60

12

​  

=  

5

1

​  

 

2 days work =  

5

2

​  

 

Remaining work = 1−  

5

2

​  

=  

5

3

​  

 

one day work of  A,B ⇒A+B=  

15

1

​  

+  

12

1

​  

=  

60

4+5

​  

=  

60

9

​  

=  

20

3

​  

 

(A+B) work for t days =  

20

3

​  

t=  

5

3

​  

 

t=4 days

A and B will complete the work in 4 days.

Step-by-step explanation: