Two men A and B can finish a work in 8 and 16 hrs respectively. If they work at it alternately for an hour A beginning first, the work will be finished in

Explanation:

Part of work done by both A and B alternatively in 2 hrs.

= 1\8+1\16=3\16

Therefore, 3\16 part of work is done in 2 hrs.

Therefore, Complete part of work is done in

2\3×16=10.66hrs.

i.e. 10 hrs. + some minutes

Part of work completed in 10 hrs.

10\2×3\16=15\16

Therefore, Remaining part of work is done by A.

i.e. 1−15\16=1\16 part of work is to be done by A.

Therefore, Time required by A to complete 1\16th part of work

= 1\2hr.

Hence total time taken by A and B alternatively to complete the work is

(10hrs+1\2hr)=10 1\2hrs.