Question

pls answer this question..

Answer 1

use the formulae of finding the nth term

a(n)=a+(n-1)(d)

      3+(n-1)(5)

     3+5n-5

      5n-2

a(20)=5(20)-2

         100-2

          98

Answer 2

Given AP is 3,8,13,...253

Here, we have to find the 20th term from the last.

So, first term a = 253.

Common difference d = 3 - 8 = (-5).

Now,

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

Here, it is asked for 20th term.

a20 = a + (20 - 1) * d

      = a + 19d

      = 253 + 19(-5)

     = 253 - 95

    = 158.

Therefore, the 20th term is 158.

Hope this helps!