Question

What is the 24th term if the arithmetic sequence where a1 = 8 and a9 = 56

Answer 1

Answer:

$a_{24} = 146$

Step-by-step explanation:

a1 = 8

a9 = 56

Using formula for finding nth term of arithmeric sequence

$a_{n} =a_{1} + (n-1)d$

We have to find 24th term, therefore n = 24

$a_{1}$ is the first term but we are missing d

d is the difference between the two consecutive terms, lets calculate it first

a9 = 56

Using the above given formula for finding d

put n = 9,  a9= 56

$a_{9} =a_{1}+ (9-1)d$

56 = 8 + 8d

8d = 48

d = 6

Getting back to main part of finding 24th term

n = 24, d = 6, a1 = 8

put values in nth term formula

$a_{n} =a_{1}+ (n-1)d$

$a_{24} = 8 + (24-1)6$

$a_{24} = 8 + 138$

$a_{24} = 146$