Question

find the 20th term from the last term of the AP 3,8,13,____253

Answer 1

the answer is your 98 of the 20th term

Answer 2

(It is the easiest answer.

Go through it rather than other complicated answers)

Simply Reverse the order of A.P

Let the new AP be

253.................13,8,3

Now the (first term) a=253 and (common difference) d= 3-8= -5

Now, 20th term of new AP will be

a(20)= a+(n-1)d

a(20)=253+(20-1)(-5)

a(20)=253+19(-5)

a(20)=253-95

a(20)= 158

Therefore, 20th term from the last term of original AP is 158.