Question

How many terms are there in the AP 9, 16, 23, 30……………282?

(a) 50

(b) 45

(c) 40

(d) 42

I had been asked this question during a job interview.

I'd like to ask this question from Arithmetic Progression Basics topic in division Arithmetic Progressions of Mathematics – Class 10

Answer 1

Correct answer is (c) 40

To explain I would say: Here a = 9 and d = 16 – 9 = 7

Let the given AP contain n terms.

Tn = 282

a + (n – 1)d = 282

9 + (n – 1)7 = 282

9 + 7n – 7 = 282

7n = 280

n = 40

Thus, the given AP has 40 terms.