3. Arithmetic Progression

Answer: (c) 4

Explanation: We have a_n = 3 + 4n
? a_{n + 1} = 3 + 4(n + 1) = 7 + 4n
? d = a_{n + 1} – a_n
= (7 + 4n) – (3 + 4n)
= 7 – 3
= 4

Answer: (c) s – r

Explanation:

Since p, q, r, s are in A.P.
? (q – p) = (r – q) = (s – r) = d (common difference)

Answer: (c) 8 – 3n