How Cheenta works to ensure student success?
Explore the Back-Story

Number of Positive Divisors | Tomato objective 98

Join Trial or Access Free Resources

This is an objective problem from TOMATO based on finding the Number of Positive Divisors.


The number of positive integers which divide $240$ is-
(A) $18$; (B) $20$; (C) $30$; (D) $24$;


We use the formula for computing number of divisors of a number:

Step 1: Prime factorise the given number

$240 = 2^4 \times 3^1 \times 5^1 $

Step 2: Use the formula for number of divisors: $(4+1) \times (1+1) \times (1+1) = 20 $

Answer: (B) 20;


Why this formula works? Basically, we are adding 1 to each exponent of each prime factor and then multiplying them. Refer to a discussion on Number Theoretic Functions (in any standard number theory book like David Burton's Elementary Number Theory).

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

2 comments on “Number of Positive Divisors | Tomato objective 98”

  1. Sir, can you plzz suggest me how to do TOMATO OBJECTIVE NO. 99 .i.e. Sum of all positive divisors of 1800

    1. You can find the formula for the sum in any standard book namely An Excursion in Mathematics,Challenges and Thrills of Pre-College Mathematics.

      Or you may surf up the google
      Use the keyword-"Sum of divisors"

      Hope this helps

Knowledge Partner

Cheenta is a knowledge partner of Aditya Birla Education Academy

Cheenta Academy

Aditya Birla Education Academy

Aditya Birla Education Academy

Cheenta. Passion for Mathematics

Advanced Mathematical Science. Taught by olympians, researchers and true masters of the subject.
ISI Entrance Solutions
ISI CMI Self Paced