Quantitative Aptitude - Arithmetic Ability Questions

All except Parrot are birds of prey.

The pattern is 1 x 2, 2 x 3, 3 x 4, 4 x 5, 5 x 6, 6 x 7, 7 x 8.

So, the next number is 8 x 9 = 72.

20% of a = b 

=> (20/100) * a = b 

 b% of 20 =(b/100) x 20 = [(20a/100)  / 100] x 20= 4a/100 = 4% of a.

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

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.

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)/n(S) = 9/20.

Let the number be x.

Then, ideally he should have multiplied by  x by 5/3. Hence Correct result was x * (5/3)= 5x/3. 

By mistake he multiplied x by 3/5 . Hence the result with error  = 3x/5 

Then, error = (5x/3 - 3x/5) = 16x/15 

Error %  = (error/True vaue) * 100 = [(16/15) * x/(5/3) * x] * 100 = 64 %

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

So, the correct next number is 1440.