Quantitative Aptitude - Arithmetic Ability Questions

The given number series is 3, 5, 13, 43, 167

3

3 x 1 + 2 = 5

5 x 2 + 3 = 13

13 x 3 + 4 = 43

43 x 4 + 5 = 177 (not equal to 167)

Hence, the odd number in the given number sequence is 167. 

The word 'OPTICAL' contains 7 different letters.

When the vowels OIA are always together, they can be supposed to form one letter.

Then, we have to arrange the letters PTCL (OIA).

Now, 5 letters can be arranged in 5! = 120 ways.

The vowels (OIA) can be arranged among themselves in 3! = 6 ways.

Required number of ways = (120 x 6) = 720.

Let the original number be x.

Final number obtained = 110% of (90% of x) =(110/100 * 90/100 * x) = (99/100)x. 

x-(99/100)x=10

=> x =1000

Total volume of water displaced =(4 x 50) cu.m = 200 cu.m

Rise in water level = 20040×20=0.25m = 25cm