Question

Choose the correct choice in the following and justify

I. 30^th term of the A.P: 10, 7, 4, …, is

A. 97 B. 77 C. − 77 D. − 87

II 11^th term of the A.P. is

A. 28 B. 22 C. − 38 D.

Answer 1

I. Given that

A.P. 10, 7, 4, …

First term, a = 10

Common difference, d = a₂ − a₁ = 7 − 10

= −3

We know that, a_n = a + (n − 1) d

a₃₀ = 10 + (30 − 1) (−3)

a₃₀ = 10 + (29) (−3)

a₃₀ = 10 − 87 = −77

Hence, the correct answer is C.

II. Given that, A.P.

First term a = −3

Common difference, d = a₂ − a₁

We know that,

Hence, the answer is B.