In the series 3, 9, 15,.............what will be the 21st term?
A. 117
B. 121
C. 123
D. 129
Answer: Option C
Solution(By Examveda Team)
Clearly, 3 + 6 = 9, 9 + 6 = 15,.............So, the series is an A.P in which a = 3 and d = 6
∴21st term = a + (21 - 1)d = a + 20d
= 3 +20 × 6 = 123.
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