Question 1

# Given: Anuj takes 1 day to complete a job. Bharat takes twice the time as Anuj to complete the same job. Chetan takes twice the time as Bharat to complete that job. Dhiraj takes twice the time as Chetan to complete that job.(A) Chetan and Dhiraj will take 8/3 days to complete the work(B) The second fastest pair to complete the work is Anuj and Dhiraj(C) The second slowest pair to complete the work is Bharat and Dhiraj(D) Bharat and Dhiraj will take 4/3 days to complete the work

Solution

Anuj takes 1 day to complete
Bharat takes 2 days
Chetan takes 4 days and Dhiraj takes 8 days to complete
option A chetan and Dhiraj together will take $$\frac{4\times\ 8}{4+8}=\frac{32}{12}=\frac{8}{3\ }days$$so A is correct.
Now calculating for all we get AB in 2/3 days AC in 4/5 days AD in 8/9 days BC in 8/6 days BD in 16/10 days
So we can say BD is 2nd slowest pair
Hence A and C are correct