Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.
1, 1, 2, 6, 24, ?, 720
Answer: Option D
Explanation:
The pattern is x 1, x 2, x 3, x 4,.....
So, missing term = 24 x 5 = 120.
2, 15, 4, 12, 6, 7, ?, ?
Answer: Option B
Let the missing terms of the series be x1 and x2.
Thus, the sequence 2, 15, 4, 12, 6, 7, x1 x2 is a combination of two series :
I. 2, 4, 6, x1 and II. 15, 12, 7, x2I consists of consecutive even numbers.
So, missing term, x1 = 8.
The pattern in II is - 3, - 5,......So, missing term, x2 = 7 - 7 = 0.
4832, 5840, 6848, ?
Answer: Option C
The pattern is + 1008.
So, missing term - 6848 + 1008 = 7856.
5824, 5242, ?, 4247, 3823
Each term in the series is obtained by subtracting from the preceding term the number
formed by the first three digits of the preceding term.
So, missing term = 5242 - 524 = 4718.
2, 8, 16, 128, ?
Each term in the series, except the first two terms, is the product of the preceding two terms.
So, missing term = 16 x 128 = 2048.