Quantitative Aptitude - Arithmetic Ability Questions

We know that 

$$\begin{gathered} 40% = 40100 = 25 \\ ⇒25 x 244 x ? = 48 \\ ? = 48 x 5 x 42 x 24 = 20 \end{gathered}$$

If the word started with the letter A then the remaining 5 positions can be filled in  5! Ways.

If it started with c then the remaining 5 positions can be filled in 5! Ways.Similarly if it started with H,I,N the remaining 5 positions can be filled in 5! Ways.

If it started with S then the remaining position can be filled with A,C,H,I,N in alphabetical order as on dictionary.

The required word SACHIN can be obtained after the 5X5!=600 Ways i.e. SACHIN is the 601th letter.

There are 12 people, so this is our n value.

So, 12C21= 66

Given Number series is :

3   4   14   48   576   27648

It follows a pattern that,

3

4

4 x 3 = 12   but not 14

12 x 4 = 48

48 x 12 = 576

576 x 48 = 27648

Hence, the odd one in the given Number Series is 14.

Let the cost of a table and that of a chair be Rs. x and Rs, y respectively.

Then, 2x + 3y = 3500 ...(i)

and 3x + 2y = 4000 .....(ii)

solving (i) and (ii) we get x = 1000, y = 500 

Next number of the sequence 1, 4, 12, 32,...

1 = 2 x 20

4 = 2 x 21

12 = 3 x 22

32 = 4 x 23

80 = 5 x 24.

Total age of 4 members, 10 years ago = (24 x 4) years = 96 years.

Total age of 4 members now = [96 + (10 x 4)] years = 136 years.

Total age of 6 members now = (24 x 6) years = 144 years.

Sum of the ages of 2 children = (144 - 136) years = 8 years.

Let the age of the younger child be x years.

Then, age of the elder child = (x+2) years.

So, x+(x+2) =8 <=> x=3

Age of younger child  =  3 years.