Quantitative Aptitude - Arithmetic Ability Questions

The given number series is 3, 11, 80, 291, 803

$$\begin{gathered} 3 \\ 3 + 23 = 3 + 8 = 11 \\ 11 + 43 = 11 + 64 = 75 (not 80) \\ 75 + 63 = 75 + 216 = 291 \\ 291 + 83 = 291 + 512 = 803 \end{gathered}$$

Let the price of the mixed variety be Rs. x per kg. By the rule of alligation, we have :

Cost of 1 kg of type 1 rice           Cost of 1 kg of type 2 rice  

∴(20-x)/(x-15) = 2/3 

⇒ 60 - 3x = 2x - 30

 ⇒ x = 18.

Here the given number series is 270, 261, 279, 252, 289, 243

270 - 9 = 261

261 + 18 = 279

279 - 27 = 252

252 + 36 = 288 (not equals to 289)

288 - 45 = 243

Hence, the odd number in the given number series is 289.

504/42 × 7 - 63 + 28 = 84 – 63 + 28 = 49

Hence option 5 is correct.

The given number series is 90 72 56 42 36 20

9 x 10 = 90

8 x 9 = 72

7 x 8 = 56

6 x 7 = 42

5 x 6 = 30 (not 36) 

4 x 5 = 20

Hence, the odd man in the given number series is 36.

The given number series follows a pattern that

11

11 - 5.5 = 5.5

5.5 + 4.5 = 10

10 - 3.5 = 6.5

6.5 + 2.5 = 9

9 - 1.5 = 7.5

Hence, the next number in the given number series is 7.5.

Pattern is

• 3

• 3 x 3.5 = 10.5

• 10.5 x 3.5 = 36.75

• 36.75 x 3.5 = 128.625

• 128.625 x 3.5 = 450.187