Question

...
) For an AP. the first and the last terms are 13 and 216 respectively. Common difference is 7 How many
terms are there in the AP? Find the sum of all the terms.
Here, a = t; = 13, tn = 216, d = 7.
ta = a + (n - 1) d
(Formula)
216 = 13 + (n - 1) x 7
(Substituting the values)
216 = 13 + 7n - 7
216 =
7n = 216 - 6
7n = 210 ..n=
There are 30 terms in the A.P.
.. (Formula)
Now, Sn =
30
S30 = 2 (13 +216)
.. (Substituting the values)
S30 =
30 terms; the sum is​

Answer 1

Sorry I don’t know. :(

Answer 2

hope it helps....

thnku