## 1. How many terms are there in 20, 25, 30 . . . . . . 140?

## 2. Find the first term of an AP whose 8^{th} and 12^{th} terms are respectively 39 and 59.

^{th}and 12

^{th}terms are respectively 39 and 59.

## 3. Find the 15^{th} term of the sequence 20, 15, 10 . . . . .

^{th}term of the sequence 20, 15, 10 . . . . .

## 4. The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is

## 5. How many terms are there in the GP 5, 20, 80, 320........... 20480?

## 6. A boy agrees to work at the rate of one rupee on the first day, two rupees on the second day, and four rupees on third day and so on. How much will the boy get if he started working on the 1st of February and finishes on the 20th of February?

## 7. If the fifth term of a GP is 81 and first term is 16, what will be the 4^{th} term of the GP?

^{th}term of the GP?

## 8. The 7^{th} and 21^{st} terms of an AP are 6 and -22 respectively. Find the 26^{th} term

^{th}and 21

^{st}terms of an AP are 6 and -22 respectively. Find the 26

^{th}term

## 9. After striking the floor, a rubber ball rebounds to 4/5^{th} of the height from which it has fallen. Find the total distance that it travels before coming to rest if it has been gently dropped from a height of 120 metres.

^{th}of the height from which it has fallen. Find the total distance that it travels before coming to rest if it has been gently dropped from a height of 120 metres.

## 10. A bacteria gives birth to two new bacteria in each second and the life span of each bacteria is 5 seconds. The process of the reproduction is continuous until the death of the bacteria. initially there is one newly born bacteria at time **t = 0**, the find the total number of live bacteria just after 10 seconds :

**t = 0**, the find the total number of live bacteria just after 10 seconds :