Question

1. find the number of terms in the given ap 18, 25 1/2 , 13, _ _ _ _ _, -47


2. choose the correct choice in the following
I. 11th of the ap :- -3, -1/2, 2 _ _ _ _

a. 28 b. 22 c. -38 d.-481/2
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Answer 1

Answer:

Correct option is

A

3n−1,74

2, 5, 8, 11, ...

a = 2, d = 5 - 2 = 8 - 5 = 3

t

n

=a+(n−1)d

=2+(n−1)3

=2+3n−3

=3n−1

t

25

=3×25−1=75−1=74