How to solve time and work problems

Topic :- Time and Work

Time and work problems are very important for test preparation when you are out of school for long period .
The time will be given and the amount of work done in that time period needs to be calculated and vice versa .

Here is a simple Time word problem Given ,Which will give an idea of solving workwordproblems
as well.
Question :-

Jim can fill a pool carrying buckets of water in 30 minutes. Sue can do the same job in 45 minutes. Tony can do the same job in 1 ½ hours. How quickly can all three fill the pool together?

Answer:-

Jim can fill the pool in 30 min.
So in 1 min,jim can fill 1/30 th part of pool.

Similarly in 1 min,Sue can fill 1/45th part of pool.

Now 1 1/2 hours = 60+30=90 min.

So in 1 min,Tony can fill 1/90 th part of pool.

Now,if all of them work together,then in 1 min,the part of the tak filled is

   1     1      1
= --- + ---- + ----
  30     45     90

Lcm=90

So by equalizing the deniminators

 1*3      1*2     1*1
------ + ----- + -------
 30*3     45*2    90*1

    3        2        1
= ------ + ------ + ------
    90       90      90

      3+2+1
=    ----------
      90

   6
= ------
   90
   1
= ----
   15

Hence,If they all work together ,The tank will be filled in 15 minutes.


For more math help,You can reply me .