Series Completion: Reasoning MCQ Question

Explanation: The given series is +2, ×2, +2, ×2, …

∴ missing number = 30 × 2 = 60

Solution: The given series is in the pattern: × 3 + 4, × 4 + 4, × 5 + 4, …..

(8 × 3) + 4 = 28; (28 × 4) + 4 = 116; (116 × 5) + 4 = 584 ; (584 × 6) + 4 = 3508

So, the missing term is 584 × 6 + 4 = 3508.

Solution: In this particular Series, the pattern is-

3 × 1 + 1 = 4; 4 × 2 + 2 = 10; 10 × 3 + 3 = 33; 33 × 4 + 4 = 136; 136 × 5 + 5 = 685;

∴ missing number = 685 × 6 + 6 = 4116.

Solution: The given series consists of squares of consecutive odd numbers i.e. 1² , 3² , 5² , 7² ,…..

So, the missing term = 9² = 81

Solution: We found that the series contains each term is one more than the product of the digits of the preceding term.

Thus (6 × 9 ) + 1 = 55, (5 × 5) + 1 = 26, (2 × 6 ) + 1 = 13, (1 × 3) + 1 = 4. Hence option (e).

Solution: In this particular series the gap between the numbers are 5, 10, 15, …so the next difference must be 20.

Than the next number be 32 + 20 = 52.

Solution: In this particular Series the numbers are arranged on percentage increase and decrease pattern. As first there is 10% decrease and than 10% increase..i.e.  105 – 10% of 105 = 94.5, 94.5 + 10% of 94.5 = 103.95 ..and so on.

Than the next number  = 93.56 + 10% of 93.56 = 102.916

Solution: The given series is following pattern: ÷5.5, ÷4.5, ÷3.5, ÷2.5, ÷1.5, ÷0.5

Than the next number = 160 ÷ 0.5 = 320

Solution: The pattern of the above Series:

16 × 0.75 = 12, 12 ×2 × 0.75 = 18, 18 × 3 × 0.75 = 40.5, 40.5 × 4 × 0.75 = 121.5, ……,

Than the next number = 455.625 × 6 × 0.75 = 2050.3125.

Solution: In this particular series the gap between the numbers are 5, 10, 15, …so the next difference must be 25.

Than the next number be 56 +25 = 81

Solution: Clearly. 5 x 2 = 10, 10 x 2 = 20, 20 x 2 – 40,… P

So. the series is a G.P. in which First term ( a) =  5 and Common ratio (r) = 2.

Let the number of terms be n.

Then, 5 x 2^n–1 = 1280

⇒2^n–1 = 256 = 2⁸

⇒n – 1 = 8 or n = 9.