Question

If the second term of an AP is 8 and 5th term is 17, find its 19th term.

Answer 1

Answer:

59

Step-by-step explanation:

$a _{2} = 8 \\ a _{5} = 17 \\ a _n = a + (n - 1)d \\ a _{2} = 8 = a + d \\a _{5} =17 = a + 4d$

Solving these simultaneous equations will give:

$17 - 8 = a + 4d - a - d \\ 9 = 3d \\ d = 3$

$a + d = 8 \\ a = 8 - 3 \\ a = 5$

$a _{19} = a + 18d \\ = 5 + 18(3) \\ = 59$