Quantitative Aptitude - Arithmetic Ability Questions

Let A, B, C be the respective events of solving the problem and A , B, C be the respective events of not solving the problem. Then A, B, C are independent event

∴A, B, C are independent events

Now,  P(A) = 1/2 , P(B) = 1/3 and P(C)=1/4

 PA=12, PB=23, PC= 34

∴ P( none  solves the problem) = P(not A) and (not B) and (not C)  

                  = PA∩B∩C 

                  = PAPBPC         ∵ A, B, C are Independent                       

                  =  12×23×34  

                  = 14  

Hence, P(the problem will be solved) = 1 - P(none solves the problem) 

                = 1-14= 3/4

Given 

6   3   3   6   24   ?

Here

6

6 x 0.5 = 3

3 x 1 = 3 

3 x 2 = 6

6 x 4 = 24 

24 x 8 = 192

The next number in the given series is 192.

The numbers are 7 x 8, 8 x 9, 9 x 10, 10 x 11, 11 x 12, 12 x 13.

So, 150 is wrong.

Here the given series 7, 11, 19, 35, ?

follows a pattern that (x 2 - 3) i.e,

7

7 x 2 - 3 = 11

11 x 2 - 3 = 19

19 x 2 - 3 = 35

35 x 2 - 3 = 67

67 x 2 - 3 = 131

Hence the next number in the given number series is 67.

Given expression = (45 x 750/100) - (25 x 480/100) = (337.50 - 120) = 217.50

Let the third number be x.

Then, first number = 120% of x =120x/100 = 6x/5  

Second number =150% of x = 150x/100 = 3x/2

Ratio of first two numbers = 6x/5 : 3x/2 = 12x : 15x = 4 : 5