Sequence And Series Question 470
Question: If the first term of an A.P. be 10, last term is 50 and the sum of all the terms is 300, then the number of terms are
[RPET 1987]
Options:
A) 5
B) 8
C) 10
D) 15
Show Answer
Answer:
Correct Answer: C
Solution:
Given that first term $ a=10 $ , last term $ l=50 $ and sum $ S=300 $
$ \therefore \ \ S=\frac{n}{2}(a+l) $
$ \Rightarrow $ $ 300=\frac{n}{2}(10+50) $
$ \Rightarrow $ $ n=10 $ .
BETA
