# Chapter 9 Sequence and Series | Class 11 Maths | Important Questions

## Chapter 9 Sequence and Series

Q1. A man saved Rs. 66000 in 20 years. In each succeeding year after the first year, he saved Rs. 200 more than what he saved in the previous year. How much did he save in the first year?

Ans: 1400

Q2. A carpenter was hired to build 192 window frames. The first day he made five frames and each day, thereafter he made two more frames than he made the day before. How many days did it take him to finish the job?

Ans: 12

Q3.  The sum of interior angles of a triangle is 180°. Show that the sum of the interior angles of polygons with 3, 4, 5, 6, … sides form an arithmetic progression. Find the sum of the interior angles for a 21 sided polygon.

Ans: 34200

Q4. In a potato race 20 potatoes are placed in a line at intervals of 4 m with the first potato 24 m from the starting point. A contestant is required to bring the potatoes back to the starting place one at a time. How far would he run in bringing back all the potatoes?

Ans: 2480

Q5. The sum of n term of arithmetic progression is 2n + 3n2. Find its second term

Ans: 16

Q6. Which term of the series 8, 4,0, ………….. is – 24 :

Ans: 9th

Q7. Find x if 2x, x + 8, 3x + 1 are in A.P.

Ans: 5

Q8. Find the 15th term from the end of the A.P. 2, 6,10, …………., 86.

Ans: 30

Q9. In an A.P. Sn = 3n2 + 5n and Tm = 164, then find m.

Ans: 27

Q10. In a cricket tournament 16 school teams participated. A sum of Rs. 8000 is to be awarded among themselves as prize money. If the last placed team is awarded Rs. 275 in prize money and the award increases by the same amount for successive finishing places, how much amount will the first place team receive?

Ans: Rs 725

Q11. The missing terms in AP: __, 13, __, 3 are:

(a) 11 and 9

(b) 17 and 9

(c) 18 and 8

(d) 18 and 9

Q12. 20th term from the last term of the A.P. 3, 8, 13, …, 253 is:

(a) 147

(b) 151

(c) 154

(d) 158

Q13. If the 2nd term of an AP is 13 and the 5th term is 25, then its 7th term is

(a) 30

(b) 33

(c) 37

(d) 38

Q14. The famous mathematician associated with finding the sum of the first 100 natural numbers is

(a) Pythagoras

(b) Newton

(c) Gauss

(d) Euclid

Q15. The sum of first 16 terms of the AP: 10, 6, 2,… is

(a) –320

(b) 320

(c) –352

(d) –400