0

Guest

Courses New

Find the sum of all two-digit odd positive numbers.

Find the sum of all two-digit odd positive numbers.

Grade:12th pass

1 Answers

Pawan Prajapati
askIITians Faculty 60787 Points
2 years ago
To find the sum of all two digit odd numbers first we need to find the total numbers of terms. We will calculate the n term of the given series with the help of arithmetic progression. The nth term in the arithmetic progression is given by an=a+(n−1)d. Complete step-by-step solution - Then we will apply the formula of sum of n terms. All two digit odd positive numbers are 11,13,15,17,........,99 which are in A.P With a=11,d=2,l=99 Let the number of terms be n. Therefore the last term is given by ⇒an=99⇒a+(n−1)d=99⇒11+(n−1)×2=99⇒(n−1)=44⇒n=45 As we know, sum of n terms is given by Sn=n2(a+l)Sn=452(11+99)Sn=45×55=2475 Hence, the sum of all two digit odd positive numbers is 2475. Note- To solve these types of questions, remember the formulas of sum of n terms of an arithmetic series, equation of nth term of arithmetic series. The question can be easily solved by substituting the values in the formula and then finding the unknown term and then substituting the values in the sum formula and after simplifying, sum is calculated.

Think You Can Provide A Better Answer ?

Other Related Questions on 10 grade maths

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More