Question

iv) For an A.P., the first and the last terms are 13 and 216 respectively. Common
difference is 7. How many terms are there in the A.P.? Find the sum of all the terms.​

Answer 1

Answer:

Hope it helps you.......

Answer 2

Answer:

an=216, a1=13, d=7, n=?

an=a+(n-1)d

216=13+(n-1)7

216-13=(n-1)7

203÷7=n-1

29=n-1

n=30

Now, S30=?

Sn=n/2(a+an)

S30=30÷2(13+216)

S30=15(229)

S30=3435

Hope it helps u.....