Question

Find the number of all natural numbers that lie between 24 and 101, which are divisible by 5.

• A. 15
• B. 16
• C. 18
• D. 20

Answer 1

The correct option is B

16

Natural numbers that lie between 24 and 101,which are divisible by 5 are 25, 30,... and 100.
This is an A.P with first term $a=25,$ common difference $d=5$ and the last term $l=100.$
But, $l=a+(n-1)d.$
$\Rightarrow 100=25+(n-1)\times 5$
$\Rightarrow 75=(n-1)\times 5$
$\Rightarrow 15=(n-1)$
$\Rightarrow 16=n$
Thus, there are 16 natural numbers between 24 and 101 that are divisible by 5.