. Choose the correct choice in the following and justify


(i) 30th term of the AP: 10, 7, 4, . . . , is

 A.   97                 B.   77

 C.   –77               D.   – 87

were

A.      28        B.      22

C.   –38               D.   – 48

 

Best Answer

Answer: Solution:(i)

Here, a = 10, d = – 3 and n = 30

We know:

an = a + (n – 1)d

Or, a30 = 10 + (30 – 1)(- 3)

= 10 – 87 = - 77

Hence,

Answer (C) – 77

(ii) Here, a = - 3, d = 5/2 and n = 11

We know that, an = a + (n – 1)d

Or, a11 = - 3 + (11 – 1) 5/2

= - 3 + 10 x (5/2) = - 3 + 25 = 22

Hence,

Answer (B) 22

 

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