Choose the correct choice in the following and justify

Question.

Choose the correct choice in the following and justify

(i) 30th term of the AP: $10,7,4, \ldots$ is

(A) 97

(B) 77

(C) $-77$

(D) $-87$

(ii) 11th term of the AP: $-3,-\frac{1}{2}, 2, \ldots$ is

(A) 28

(B) 22

(C) $-38$

(D) $-48 \frac{1}{2}$


Solution:

(i) $a=10, d=-3$

$\mathrm{t}_{30}=\mathrm{a}+29 \mathrm{~d}=10+29 \times(-3)$

$=10-87=-77$

Hence, the correct option is (C)

(ii) $\mathrm{a}=-3, \mathrm{~d}=5 / 2$

$\mathrm{t}_{11}=\mathrm{a}+10 \mathrm{~d}=-3+10 \times 5 / 2=22$

Hence, the correct option is (B)

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