Question

There's an arithmetic sequence having 9 terms. the sum of 1st and 9th term is 32
(a) what is the 5 th term?​

Answer 1

Step-by-step explanation:

Let first term = a, common difference = b,

t1 = a , t9 =

$a + (9–1) \times b$

=

$a + 8b$

, according to condition ,

$a+a+8b = 24$

…..(1),

When we find the sum of first nine terms , we have first term is a , and last term l = a+8b, number of total terms , n= 9,

S =

$\frac{n}{2} \times \: {a+l}$

=

$\frac{9}{2} \times {a +a+8b}.$

Now putting a+a+8b = 24 from equation (1)

n/2*{a+l} = 9/2*{a +a+8b}. Now putting a+a+8b = 24 from equation (1)

S = (9/2)*24 =108

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Hope it will be Helpful

Answer 2

I hope that u got the correct answer..