Series Completion - Study Mode

[#141] Which term of the series 5, 8, 11, 14,.....is 320?
Correct Answer

(C) 106th

Explanation

Solution: Clearly, 5 + 3 = 8, 8 + 3 = 11, 11 + 3 = 14, ..... So, the series is an A.P. in which a - 5 and d = 3. Let 320 be the nth term of the series. Then, 320 = 5 + (n - 1) x 3 or (n - 1) = 105 or n = 106.

[#142] 8, 9, 8, 7, 10, 9, 6, 11, 10, ?, 12
Correct Answer

(A) 5

Explanation

Solution: The given sequence is a combination of three series : I. 1st, 4th, 7th, 10th terms i.e. 8, 7, 6, ? II. 2nd, 5th, 8th, 11th terms i.e. 9, 10, 11, 12 III. 3rd, 6th, 9th terms i.e. 8, 9, 10 The pattern in I is - 1. So, missing term = 6 - 1 = 5.

[#143] 3, 7, 15, ?, 63, 127
Correct Answer

(B) 31

Explanation

Solution: Each number in the series is one more than twice the preceding number. So, missing term = (15 x 2) + 1 = 31.

[#144] 4, 10, ?, 82, 244, 730
Correct Answer

(B) 28

Explanation

Solution: Each number in the series is 2 less than thrice the preceding number. So, missing number = (10 x 3) - 2 = 28.

[#145] 13, 32, 24, 43, 35, ?, 46, 65, 57, 76
Correct Answer

(C) 54

Explanation

Solution: The given sequence is a combination of two series: I. 13, 24, 35, 46, 57 and II. 32, 43, ?, 65, 76 The pattern in both I and II is + 11. So, missing term = 43 + 11 = 54.