Question

this is A.P question

Answer 1

Answer:

Step-by-step explanation:

Tn=a+(n-1)d

216=13+(n-1)*7

n=30

Hence total no of terms are 30

Now,

Sn=n/2(2a+(n-1)d)

Sn=30/2(2*13+29*7)

Sn=3435

Hence the sum is 3435

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Answer 2

In an A.P ‘n’ which used here is subscript.

→ an = a + (n - 1)d

→ 216 = 13 + (n - 1)7

→ 216 - 13 = (n - 1)7

→ 203/7 = n - 1

→ 29 + 1 = n

→ n = 30

Hence total terms in A.P are 30.

______________________________

→ Sn = n/2[2a + (n - 1)d]

→ S30 = 30/2[2(13) + (30-1)7]

→ S30 = 15(26 + 203)

→ S30 = 15 × 229

→ S30 = 3435

Sum of 30 terms in A.P are 3435.