Question Discussion & Solution

CALCULATIONS:

21² - 21 = 441 - 21 = 420

22² - 22 = 484 - 22 = 462

23² - 23 = 529 - 23 = 506

24² - 24 = 576 - 24 = 552

25² - 25 = 625 - 25 = 600

26² - 26 = 676 - 26 = 650

The pattern of given series is:

→ 15 = 7 + 8

→ 27 = 15 + 12

→ 43 = 27 + 16

→ 63 = 43 + 20

The difference increases by 4.

Calculation:

The series follows following pattern:

⇒ 5 + 0 = 5

⇒ 5 + 5 = 10

⇒ 10 + 10 = 20

⇒ 20 + 15 = 35

⇒ 35 + 20 = 55

⇒ 55 + 25 = 80

∴ The missing number is 80

The series follows the following pattern:

346 - 22 = 342

342- 32 = 333

333 - 52 = 308

308 - 72 = 259

259 - 112 = 138

∴ The wrong term in the series is 178.

24 × 1 + 5 = 29

29 × 2 + 4 = 62

62 × 3 + 3 = 189

189 × 4 + 2 = 758