Q. A can do a job in 10 days and B can do it in 20 days. In how many days working together they will complete the same job?
Answer:
Step: 1
Take LCM of 10, 20 that is 20 now suppose it as total work.
Step: 2
20/10 > 2 w/d is A efficiency.
20/20> 1 w/d B efficiency.
Step: 3
ADD 2+1 because they are working together its 3 w/d.
Step: 4
20/3 = 6 2/3 days answer.