Question

30) In an AP the 4th term is 1/6 and the 6th term is 14, prove that the sum of its first 24
terms is 25/2.​

Answer 1

Step-by-step explanation:

ANSWER

Given, 14

th

term =6, 6

th

term =14

WE know T

n

=a+(n−1)d

Therefore, 6=a+(14−1)d=a+13d ....(1)

and 14=a+(6−1)d=a+5d ....(2)

Subtracting equations (1) and (2),

d=8d=−8⇒d=−1

Putting this value in equation (1), we get

6=a+13(−1)

⇒a=6+13

⇒a=19

Thus T

95

=a+(95−1)d

=a+94d

=19−94=−75