R S Aggarwal Solutions for Exercise 1: EXERCISE 1

The sum of first $7$ terms of an $\mathrm{AP}$ is $10$ and the sum of next $7$ terms is $17$. What is the $3^{rd}$ term of the $\mathrm{AP}?$

The sum of first $80$ natural numbers is 

The sum of all even natural numbers between $300$ and $400$ is

The sum of all odd numbers between $100$ and $200$ is 

The sum of all positive integral multiples of $3$ less than $100$ is

How many terms of an $\mathrm{AP} 6,12,18,24,\dots$  must be taken to make the sum $816?$

The sum of all $3-$digit numbers divisible by $5$ is

The sum of $n$ terms of an $\mathrm{AP}$ is $\left(3n^2+2n\right)$. Its common difference is