Neha Tyagi and Amit Rastogi Solutions for Chapter: Arithmetic Progressions, Exercise 3: Exercise

If sum of first $6$ terms of an AP is $36$ and that of the first $16$  terms is $256$, then first find the sum of first $10$ terms.

Find the sum of all the $11$ terms of an AP whose middle most term is $30.$

Find the sum of last ten terms of the AP, $8, 10, 12, ..., 126.$

Find the sum of first seven numbers which are multiples of $2$ as well as of $9$.

How many terms of the AP$-15, -13, -11, ...$ are needed to make the sum $-55$?

The sum of the first $n$ terms of an AP whose first term is $8$ and the common difference is $20$ is equal to the sum of first$2n$ terms of another AP whose first term is $-30$ and the common difference is $8$. Find $n$.

Kanika was given her pocket money on $\mathrm{Jan} 1\mathrm{st}, 2008$. She puts $₹1$ on day $1, ₹2$ on day, $2, ₹3$ on and continued doing so till the end of the month. From this money into her piggy bank, she also spent $₹204$ of her pocket money, and found that at the end of the month she still had $₹100$ with her. How much was her pocket money for the month?

Yasmeen saves $\mathrm{Rs}. 32$during the first month, $\mathrm{Rs}. 36$ in the second month and $\mathrm{Rs}. 40$ in the third month. If she continues to save in this manner, in how many months will she save $\mathrm{Rs}. 2000?$