Q27 of 178 Page 559

The 2nd term of an AP is 13 and its 5th term is 25. What is its 17th term?

Given: a₂ = 13

a₅ = 25

To find: a₁₇

Consider a₂ = 13

⇒ a + d = 13 …………….(1)

Consider a₅ = 25

⇒ a + 4d = 25 …………….(2)

Subtracting equation (1) from equation (2), we get,

3d = 12

⇒ d = 4

∴ Common difference = 4

From equation (1), we get

a = 13 - d

= 13 - 4

= 9

Thus a₁₇ = a + 16d

= 9 + 16(4)

= 73

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

How many terms of the AP 3, 7, 11, 15, ... will make the sum 406?

The 17th term of an AP exceeds its 10th term by 21. The common difference of the AP is

The 8th term of an AP is 17 and its 14th term is 29. The common difference of the AP is