Quantitative Aptitude - TIME AND WORK

TIME AND WORK

* If A can do a piece of work in n days , then  A's  1 day work =1/n


* If A's  1 day work =1/n, then  A can finish a work in =n days


*  If A is thrice as good workman as B,then: Ratio of work done by A and B =3:1. Ratio of time taken by A and B to finish a work=1:3


*  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.

*  If A can finish work in X time and A and B together can finish 
work in S time then B can finish work in (XS)/(X-S) time.

* 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

* If A can finish work in X time and B in Y time and A,B and C 
together in S time then :
  ---->C can finish work alone in (XYS)/ (XY-SX-SY)
  ---->B+C can finish in (SX)/(X-S)
  ---->A+ C can finish in (SY)/(Y-S)

Quantitative Aptitude - PROFIT AND LOSS

Suppose the price is first increase by X%  and then decreased 

by Y% , the final change % in the price is given by the following 

formula,

                       Final Difference % = X- Y – XY/100

EXAMPLE 1. : The price of T.V set is increased by 40 % of the 

cost price and then decreased by 25% of the new price .  On 

selling, the profit for the dealer was Rs.1,000 . At what price was 

the T.V sold.

From the above mentioned formula you get : 

Final difference % = 40-25-(40*25/100)= 5 %.
So if 5 % = 1,000
then 100 % = 20,000.
C.P = 20,000
S.P = 20,000+ 1000= 21,000.

EXAMPLE 2 : The price of T.V set is increased by 25 % of cost 

price and then decreased by 40% of the new price .  On selling, 

the loss for the dealer was Rs.5,000 . At what price was the T.V 

sold.

From the above mentioned formula you get : 

Final difference % = 25-40-(25*45/100)=  -25 %.
So if 25 % = 5,000
then 100 % = 20,000.
C.P = 20,000
S.P = 20,000 – 5,000= 15,000.