Question

if a can do a work in 60 days and B can do a work in 40 days if C joins after three days can do the same work in 30 days then the number of days taken to complete the work is

Answer 1

lcm of 60, 40 and 30 = 120

efficiency of A,B and C = 2,3,4

in first 3 days A and B did = (2+3)*3 = 15 unit of work

Now C also joins.

all one day work now = 2+3+4 = 9 unit

remaining work = 120-15 = 105 unit

they will do in = 105/9 = 35/3 days .

total number of days to complete the work is = 3+35/3 = 44/3 = 14(2/3) days . ☺️

[ mark as brainlist if you understand my solution]