66, 36, 18, ?
Answer: Option C
Explanation:
Each term in the series is the product of the digits of the preceding term.
So, missing term = 1 x 8 = 8.
In the series 3, 9, 15, ...... what will be the 21st term?
Clearly, 3 + 6 = 9, 9 + 6 = 15,.....
So, the series is an A.P. in which a = 3 and d = 6.
Therefore 21st term = a + (21 - 1) d = a + 20d = 3 + 20 x 6 = 123.
28, 33, 31, 36, ?, 39
Answer: Option B
The pattern is + 5, - 2, + 5, - 2,.....
So, missing term = 36 - 2 = 34.
1, 9, 25, 49, 81, ?
The series consists of squares of consecutive odd numbers
i.e. 12, 32, 52, 72, 92,.....
So, missing term = 112 = 121.
1, 9, 25, 49, ?, 121
The given series consists of squares of consecutive odd numbers
i.e. 12, 32, 52, 72,.....
So, missing term = 92 = 81.
