Question

a can do a piece of work in 20 days which B alone can do in 12 days B worked at it for 9 days a can finish the remaining work in?? right answer is 5 ​

Answer 1

20,12 lcm = 60

efficiency of A and B = 3, 5

B work for 9 days means he did = 9*5 = 45 unit ,

left work to be done = 60-45 = 15 unit,

Now this done by A in = 15/3 = 5 days (ans.)

[ mark as brainlist if you understand .]