Quantitative Aptitude - Arithmetic Ability Questions

Go on multiplying the given numbers by 2, 3, 4, 5, 6.

So, the correct next number is 1440.

Let S be the sample space

Then n(S) = no of ways of drawing 2 balls out of (6+4) =10C2 10 =10*92*1 =45

Let E = event of getting both balls of same colour

Then,n(E) = no of ways (2 balls out of six) or (2 balls out of 4)

                =6C2+4C2 = 6*52*1+4*32*1= 15+6 = 21

Therefore, P(E) = n(E)/n(S) = 21/45 = 7/15

There are two series (8, 11, 14, 17, 20) and (7, 12, 17, 22) increasing by 3 and 5 respectively.

Let the numbers be 3x, 4x and 5x.

Then, their L.C.M. = 60x.

So, 60x = 2400 or x = 40.

 The numbers are (3 x 40), (4 x 40) and (5 x 40).

Hence, required H.C.F. = 40.

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.

Given number series is 12  9  13.5  30.3  ?  341.7

Here the pattern followed by the series is

12 

12 x 0.75 = 9

9 x 1.5 = 13.5

13.5 x 2.25 = 30.3

30.37 x 3 = 91.12

91.12 x 3.75 = 341.71

Hence, the missing number in the sequence is 91.12.

Subtract 1, 3, 5, 7, 9, 11 from successive numbers.

So, 34 is wrong.