Question

in a certain A.P,the 24th term is twice the 10th term. prove that the 72nd term is twice the 34th term.​

Answer 1

Answer:

Let the first term and the common difference be "a" and "d"

Given. T24 = 2 T10

or, a + 23d = 2(a + 9d)

= 2a + 18d

or, a = 5d ……………… (i)

Now, T34 = a + 33d

= 5d + 33d Using (i)

= 38d ............. (ii)

T72 = a + 71d

= 5d + 71d Using(i)

= 76d

= 2 x 38d

= 2 x T34 using(ii)

Proved

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