APTITUDE TRICKS2-

TIME AND WORK :

1.  If A can finish work in X time  and B can finish work in Y time 

     then both together can finish work in (X*Y)/ (X+Y) time.

2.  If A can finish work in X time and A and B together can work in Y  time

     time then B can finish work in  (XY)/(X-Y) time.

3.  If A can finish work in X time and B in Y time and C in Z time 

     then they all working together will finish the work in

    (XYZ)/ (XY +YZ +XZ) time

4 .  If A can finish work in X time and B in Y time and A,B and C 

    together in Z time then :

    C can finish work alone in (XYZ)/ (XY-ZX-ZY)

    Similar can be done for A&B alone-

     B+C can finish in (ZX)/(X-Z)

 & A+ C can finish in (ZY)/(Y-Z)

Here is another shortcut

TYPE 1 :  Price of a commodity is increased by 60 %. By how 
                much % should the consumption be reduced so that the 
                expense remain the same.

TYPE 2 :  Price of a commodity is decreased by 60 %. By how 
                 much % can  the consumption be increased so that the expense 
                 remain the same.

Solution :  
TYPE1 :   (100* 60 ) / (100+60) = 37.5 %
TYPE 2 :   (100* 60 ) / (100-60) = 150  %


More Tricks will be soon.......