Quantitative Aptitude - Arithmetic Ability Questions

In a simultaneous throw of two dice, n(S) = 6 x 6 = 36

Let E = event of getting a doublet = { (1,1), (2,2), (3,3), (4,4), (5,5), (6,6)}

 P(E)=n(E)n(S)=636=16

A                   B                 C

3x                 4x                5x 

(3x+x)          2x               (5x+x)         (B Gives 1/4 to A and 1/4 to C) 

=4x              2x                 6x 

(4x+x)          2x                 5x              ( C Gives 1/6 to A) 

=5x              2x                 5x

Therefore, 5 : 2 : 5

Let the present ages of A and B be 'x' and 'y' respectively

From the given data, 

[(x-2) + (y-2)]/2 = 26

=> x+y = 56

But given the age of A, 5 years hence is 40 yrs => present age of A = 40 - 5 = 35 yrs

=> x = 35 => y = 56 - 35 = 21

=> Age of B = 21 yrs

Given B is 5 years younger to C,

=> Age of C = 21 + 5 = 26 yrs

=> Required Difference between ages of A and C = 35 - 26 = 9 yrs.

Let the number be 'N'
Given N + 30N/100 = 390
=> 130N/100 = 390
=> N = 390 x 10/13
=> N = 300.

Given length of iron rod =7 mts and  and diameter of rod = 2 cms 

=> r = 1/100 mts

Therefore,  Volume of one rod = πr2h cu. m =  227×11002×7cu. m = 115000 cu. m

Given volume of iron = 0.88 cu. m 

Therefore, Number of rods = 0.88×500011 = 400.

At the moment the paint is 3 liters of paint and 3 liters of water. We need to add to this to make the new ratio 2 liters paint to 1.5 liters water. As this is equivalent to 4 : 3 we can see that we have the right amount of water, and just need 1 liter of paint to make it correct.

only (c) is correct since it is divisible by 4.

Let the original number of element  be x then the new no.of elements will be 

            4x5 = K                               

So K must be divisible by 4

Since,      x =  Kx5/4