Quantitative Aptitude - Arithmetic Ability Questions

  4             3             4             7               15        ?
×1-1      ×1+1       ×2-1       ×2+1           ×3-1

15x3 - 1 = 45 - 1 = 44

Given 311   230   294   ?   281   256

311 - (9x9) = 230

230 + (8x8) = 294

294 - (7x7) = 245

245 + (6x6) = 281

281 - (5x5) = 256

Hence, the missing number in the given series is 245.

Let the quantity of the wine in the cask originally be x litres

 
Then, quantity of wine left in cask after 4 operations =x1-8x4litres

∴x1-8x4x = 1681  

 ⇒1-8x4=234 

⇒x=24

C.P. of 56 kg rice = Rs. (26 x 20 + 30 x 36) = Rs. (520 + 1080) = Rs. 1600.

S.P. of 56 kg rice = Rs. (56 x 30) = Rs. 1680.

Gain =(80/1600*100) % = 5%

Given fraction is 5 (2/7) - 3 (1/14) - 2 (1/14) - 1 (1/7) = ? + 3 (1/17) 

It can be written as 

(5 - 3 - 2 - 1) + (2/7 - 1/14 - 1/14 - 1/7) = ? +  3 (1/17) 

-1 + 0 - 3 (1/17) = ?

=> ? = -4 (1/17)

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

Here the given number series is 2 4 27 256 3125 46656

It follows a pattern that,

$$\begin{gathered} 11 = 1 \\ 22 = 4 \\ 33 = 27 \\ 44 = 256 \\ 55 = 3125 \\ 66 = 46656 \end{gathered}$$

Hence the wrong number in the given number series is 2 instead of 1.

The series follows the following pattern

5 X 5 – 5 = 20

20 X 4 – 4 = 76

76 X 3 – 3 = 225

225 X 2 – 2 = 448

Hence, the term 225 denoted by (d) completes the series