Quantitative Aptitude - Arithmetic Ability Questions

The given series of numbers follow the rule that,

2880/6 = 480
480/5   = 96
96/4     = 24
24/3     = 8
8/2       = 4
4/1       = 4

But 92 is not in the rule. It is the wrong number in the given series.

The given series 

12   24   26.5   79.5   ?   330 follows a pattern that,

12 x 2 = 24

24 + 2.5 = 26.5

26.5 x 3 = 79.5

79.5 + 3 = 82.5

82.5 x 4 = 330

Hence, the missing number is 82.5

Let original length = x and original breadth = y.

Original area = xy. 

New length = x/2 and New breadth=3y 

New area = 32xy 

Therefore,  Increase in area = New area-original area = 32xy-xy=12xy 

Therefore,  Increase % = increase in area original area*100=12xyxy*100=50 %

Given number series is 9 17 11 19 13 

Here the pattern is

• 9

• 9 + 8 = 17

• 17 - 6 = 11

• 11 + 8 = 19

• 19 - 6 = 13

• 13 + 8 = 21

• 21 - 6 = 15

• 15 + 8 = 23

let ABCD be the given parallelogram 

area of parallelogram ABCD = 2 x (area of triangle ABC) 

now a = 30m, b = 14m and c = 40m

 s=1/2 x (30+14+40) = 42 

Area of triangle ABC = ss-as-bs-c  

= 4212282= 168sq m 

area of parallelogram ABCD = 2 x 168 = 336 sq m

Required number of ways = (7C5*3C2) = (7C2*3C1) = 63

Here S= {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH}.

Let E = event of getting at least two heads = {THH, HTH, HHT, HHH}.

P(E) = n(E) / n(S)

      = 4/8= 1/2

Suppose the can initially contains 7x and 5x litres of mixtures A and B respectively

Quantity of A in mixture left =7x-712×9=7x-214 litres.

Quantity of B in mixture left =  5x-512×9=5x-154litres.

7x-2145x-154+9=79

⇒28x-2120x+21=79

⇒x=3

 So, the can contained 21 litres of A.