The sum of two numbers is 126 and their diff is 18. Find the numbers.


Ans:
        x+y=126
        x-y=18
       
      so, 2x=144 and x=72
      so, 72+y=126
      y=126-72=54


so, the two numbers are 72 and 54. 

A,B,C partners invest 1600, 1800, 2300. Divide profit of 399Rs.

Ans:
      16+18+23=57
      16/57*399= Ans.
      18/57*399= Ans.
      23/57*399= Ans.

IIf asked.."In How Many Ways.."

(n-1)!=permutation
Suppose, in how many ways, 8 persons can be seated in a round table conference?


Ans:
       (n-1)! = 7!= 5040 Ans

See Short Cut Method

8 1/3 % of ? = 150

 25/3 * ? = 150

 ?= 150*3/25
   =18

X,Y,Z share money in ratio of 7:8:16. If Z receives Rs. 27 more than X, then find the total money.

Ans:
      7x, 8x, 16x
      16x= 7x + 27
       9x=27
         x=3
    
     7x+8x+16x = 31x=31*3= 93 Rs.

Money deposited by P,Q,R in ratio of 3:5:7. Q's share is 1500. What is the difference between p and Q's share?

Ans: 3x,5x,7x
    Q=5x=1500
           x=300

    P=900
    R=2100
   
    Diff=2100-900=1200

If a:b=2:3, b:c=4:5, then find ratio of a:b:c?

Ans:
        a : b : c
        2   3
             4   5

        a=2*4=8
        b=3*4=12
        c=3*5=15


Ans: 8:12:15


Q & A:

a:b=2:3
b:c=4:5
c:d=6:7

a : b : c : d
2   3
     4   5 
          6   7

a=2*4*6=48
b=3*4*6=72
c=3*5*6=90
d=3*5*7=105

48:72:90:105

If it takes 10 days to die a trench of 100 m long, 50 m broad, 10 m deep, what length of trench, 25 m broad, 15 m deep can be dug in 30 days?

Ans:

       D          L            B            D

      10        100         50           10

      30         x            25           15

     x=100*30*50*10/10*25*15

       = 400m

20 Men-20 Days
25 Men-??days

   =20*20/25
   =16 days


14 Pumps-6 Days
?? Pumps-4 Days

   = 14*6/4
   = 21 days

5 chairs cost as much as 12 stools, 7 stools cost as much as 2 tables, 3 tables cost as much as 2 sofas. If the cost of  5 sofas be Rs. 8750. Find that of a chair.

Ans:
        x rupees=1 chair
        5 chair=12 stools
        7 stools=2 tables
        3 tables=2 sofas
        5 sofas= 8750/-

        x=1*12*2*2*8750/5*7*3*5
          =800/-

A factory produces 470 toy-cars a day. How many cars did it produce in the year 1988, if there are 86 holidays? [Hint: 1988 is a leap year]

Ans: 366-86=280
        =470*280=131600


A factory produces 144 ball-pens in a carton. They have 395 cartons to be filled. They have already made 57000 ball-pens. Do they need to make more ball-pens in order to fill all the cartons?


Ans: 395*144=56880= NO NEED  

Place Value

Find the place value:
7 in 87930= 7000

diff between the place values:
two fours in 12494=400-40=360

Smallest whole number =0

Smallest counting number=1

Probability

				http://www.indiabix.com/aptitude/probability/
				Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5? A. 1 2 B. 2 5 C. 8 15 D. 9 20 Answer & Explanation  Answer: Option D Explanation: Here, S = {1, 2, 3, 4, ...., 19, 20}. Let E = event of getting a multiple of 3 or 5 = {3, 6 , 9, 12, 15, 18, 5, 10, 20}. P(E) = n(E) = 9 . n(S) 20

Maths

	Six years ago, the ratio of the ages of Kunal and Sagar was 6 : 5. Four years hence, the ratio of their ages will be 11 : 10. What is Sagar's age at present?
	A. 16 years B. 18 years C. 20 years D. Cannot be determined E. None of these Answer: Option A Explanation: Let the ages of Kunal and Sagar 6 years ago be 6x and 5x years respectively. Then, (6x + 6) + 4 = 11 (5x + 6) + 4 10 10(6x + 10) = 11(5x + 10) 5x = 10 x = 2. Sagar's present age = (5x + 6) = 16 years

Maths

How many 3-digit numbers can be formed from the digits 2, 3, 5, 6, 7 and 9, which are divisible by 5 and none of the digits is repeated?

	A.	5		B.	10
	C.	15		D.	20

Answer: Option D

Explanation:
Since each desired number is divisible by 5, so we must have 5 at the unit place. So, there is 1 way of doing it.
The tens place can now be filled by any of the remaining 5 digits (2, 3, 6, 7, 9). So, there are 5 ways of filling the tens place.
The hundreds place can now be filled by any of the remaining 4 digits. So, there are 4 ways of filling it.
Required number of numbers = (1 x 5 x 4) = 20.

For Shapes Identification

http://www.thatquiz.org/tq-f/math