Question: How many natural numbers are there between 23 and 100 which are exactly divisible by 6 ?
[A].8
11
12
13
[A].
[B].
[C].
[D].
Answer: Option D
Explanation:
Required numbers are 24, 30, 36, 42, …, 96
This is an A.P. in which a = 24, d = 6 and l = 96
Let the number of terms in it be n.
Then tn = 96 a + (n – 1)d = 96
24 + (n – 1) x 6 = 96
(n – 1) x 6 = 72
(n – 1) = 12
n = 13
Required number of numbers = 13.