How many two-digit natural numbers are divisible by ?
Step 1: Identify the given sequence as an arithmetic progression
The first two digit natural number divisible by is
The last two digit natural number divisible by is
The sequence of numbers which is divisible by is an arithmetic progression with term and common difference of
Step 2 : Finding the number of terms in an arithmetic progression
The term of an arithmetic progression is given as
Here,
Hence, the number of two digit natural numbers divisible by is