Q2 of 178 Page 526

Find:

the 20th term of the AP 9, 13, 17, 21, ... .

Here, First term = a = 9

Common difference = d = 13 - 9 = 4


To find = 20th term, ∴ n = 20


Using the formula for finding nth term of an A.P.,


an = a + (n - 1) × d


∴ an = 9 + (20 - 1) × 4


⇒ an = 9 + 19 × 4 = 9 + 76 = 85


∴ 20th term of the given AP is 85.


More from this chapter

All 178 →
1

Show that each of the progressions given below is an AP. Find the first term, common difference and next term of each.

√2, √8, √18, √32,…

 1

Show that each of the progressions given below is an AP. Find the first term, common difference and next term of each.

√20, √45, √80, √125,…

 2

Find:

the 35th term of the AP 20, 17, 14, 11, .

 2

Find:

the 18th term of the AP √2, √18, √50, √98….