Question

For what value of k:3k,k+9 and 8k+9 are in a.p.?

Answer 1

Answer:

a=3k

d=k+9-3k

d=9-2k

a3=a+2d

8k+9=3k+2 (9-2k)

8k+9=3k+18-4k

8k=18-k

8k+k=18

9k=18

k=2

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