Welcome to the NCERT Solutions for Class 11 Mathematics - Chapter Sequence and Series. This page offers a step-by-step solution to the specific question from Exercise 5, Question 5: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.
Find the sum of integers from 1 to 100 that are divisible by 2 or 5.
The integers from 1 to 100, which are divisible by 2, are 2, 4, 6… 100.
This forms an A.P. with both the first term and common difference equal to 2.
⇒100 = 2 + (n –1) 2
⇒ n = 50
The integers from 1 to 100, which are divisible by 5, are 5, 10… 100.
This forms an A.P. with both the first term and common difference equal to 5.
∴100 = 5 + (n –1) 5
⇒ 5n = 100
⇒ n = 20
The integers, which are divisible by both 2 and 5, are 10, 20, … 100.
This also forms an A.P. with both the first term and common difference equal to 10.
∴100 = 10 + (n –1) (10)
⇒ 100 = 10n
⇒ n = 10
∴Required sum = 2550 + 1050 – 550 = 3050
Thus, the sum of the integers from 1 to 100, which are divisible by 2 or 5, is 3050.
NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:
Stay updated with our latest educational content and study tips
After preparation for NEET and JEE, students inclined towards studying under state education boards find themselves a step behind the CBSE students. The syllabus, question pattern and level of idea of these national entrance exams varies widely from most state board syllabus. But with the correct approach, students taking the state board can hold their … Read more
Read MoreInterest is one of the most significant ideas in maths and financial calculations. It is very common in banking, loan applications, investments, saving account and competitive exams. Simple Interest and Compound Interest make it easier to find out how much more is earned and/or paid on a principal during the period of time. These Interest … Read more
Read MoreIn 2026, students, professionals, and job seekers must have a high level of spoken English. Spoken English is a beginner level course to enhance learners’ communication skills in English, their pronunciation, vocabulary, grammar structure and confidence in speaking English fluently. Today, the emphasis of spoken English courses is placed on actual conversations, everyday speech practice … Read more
Read MoreArtificial Intelligence (AI) and Machine Learning (ML) are two of the most sought-after technologies in today’s digital era. Although these terms are often used together, they are not the same. Machine Learning is, in fact, a component of Artificial Intelligence that enables systems to learn and enhance on their own, without direct programming. AI is … Read more
Read MoreWelcome to the NCERT Solutions for Class 11 Mathematics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 5 , Question 5: Find the sum of integers from 1 to 100 that are divisible by 2 or 5.....
Comments
The answer was helpful but can we write directly the integers divisible by both 2 or 5??
The answer was helpful but can we write directly the integers divisible by both 2 or 5??
Thanks for the solution.
That is correct but I have asked other answer
Great..
Thanks sir it helped me
thanks sir.. ... wonderful answer.....
Thanks a lot
Thanks sir
Can it be solved by n(n+2)/2