Question for today

TIME AND WORK
Points for recapitulation while solving problems on time and work:
1. If a person can do a piece of work in ‘m’ days, he can do 1/m of the work in 1 day.
2. If the number of persons engaged to do a piece of work be increased (or
decreased) in a certain ratio the time required to do the same work will be
decreased (or increased) in the same ratio.
3. If A is twice as good a workman as B, then A will take half the time taken by B to
do a certain piece of work.
4. Time and work are always in direct proportion.
5. If two taps or pipes P and Q take ‘m’ and ‘n’ hours respectively to fill a cistern or
tank, then the two pipes together fill (1/m)+(1/n) part of the tank in 1 hour and the
entire tank is filled in 1/((1/m)+(1/n)) = mn/(m+n) hours.


Example:
1. If 12 men can do a piece of work in 36 days. In how many days 18 men can do
the same work?
Solution:
12 men can do a work in 36 days.
18 men can do the work in (12/18)*36=24 days.
Note:
If the number of men is increased, the number of days to finish the
work will decrease.