In each of the following questions, a number series is given with one term missing. Choose the correct alternative that will continue the same pattern.
625, 5, 125, 25, 25, ?, 5
Answer: C
The given sequence is a combination of two series :
I. 625, 125, 25, 5 and II. 5, 25, ?
The pattern in I is ÷ 5, while that in II is x 5. So, missing term = 25 x 5 = 125.
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2,2,5, 13,28,?
Answer: D
The pattern is + 0, + 3, + 8, + 15, ..... i.e. + (l2 - 1), + (22 - 1), + (32 - 1), + (42 - 1), .....
So, missing term = 28 + (52 - 1) = 28 + 24 = 52.
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1, 4, 10, 22, 46, ?
Answer: C
Explanation:
The pattern is + 3, + 6, + 12, + 24,.....
So, missing term = 46 + 48 = 94.
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120, 99, 80, 63, 48, ?
Answer: A
Explanation:The pattern is – 21, – 19, – 17, – 15,…..So, missing term = 48 – 13 = 35.
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589654237, 89654237, 8965423, 965423, ?
Answer: D
Explanation:The digits are removed one by one from the beginning and the end in order alternatelyso as to obtain the subsequent terms of the series.
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3, 10, 101,?
Answer: C
Explanation:Each term in the series is obtained by adding 1 to the square of the preceding term.So, missing term = (101)2 + 1 = 10202
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In the series 2, 6, 18, 54, …… what will be the 8th term ?
Answer: B
Explanation:Clearly, 2 x 3 = 6, 6 x 3 = 18, 18 x 3 = 54,…..So, the series is a G.P. in which a = 2, r = 3.Therefore 8th term = ar8-1 = ar7 = 2 x 37 = (2 x 2187) = 4374.
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24, 60, 120, 210, ?
Answer: B
The pattern is + 36, + 60, + 90,.....i.e. + [6 x (6 + 0)], + [6 x (6 + 4)], + [6 x (6 + 9)],...
So, missing term = 210 + [6 x (6 + 15)] = 210 + 126 = 336.
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1, 9, 25, 49, ?, 121
Answer: B
The given series consists of squares of consecutive odd numbers i.e. 12, 32, 52, 72,.....
So, missing term = 92 = 81.
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28, 33, 31, 36, ?, 39
Answer: B
Explanation:
The pattern is + 5, - 2, + 5, - 2,.....
So, missing term = 36 - 2 = 34.
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