Question

n^th term of a series 3,8,13,18......is
Please give the full solution.

Answer 1

Here is the solution:

Let the first term be a.

Let the common difference be d.

We know that nth term is a+(n-1)d

a=3

d=8-3=5

So:

nth term is a+(n-1)d

=3+n*5-5

=3+5n-5

=5n-2

Hope it helps you.

Answer 2

Let a be the first and d be the common difference.

Here, First term a = 3,

Common difference d = 8 - 3

                                     = 5.

Now,

We know that nth term of an AP an = a + (n - 1) * d

                                                           = 3 + (n - 1) * 5

                                                           = 3 + 5n - 5

                                                           = 5n - 2.

Therefore, nth term of an AP an : 5n - 2.

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Now,

You are saying that your answer is 100.

First term a = 3.

Last term an = 100

Common difference d = 5.

We know that an = a + (n - 1) * d

⇒ 100 = 3 + (n - 1) * 5

⇒ 100 = 3 + 5n - 5

⇒ 100 = 5n - 2

⇒ 102 = 5n

⇒ n = 20.4.

Therefore, your answer is incorrect!

Hope it helps!