Question

first term is 200 and last term is 2000 and common difference is 20 .find the number of terms.

Answer 1

this is the answer for your question.

Answer 2

here in an AP
an = (a+(n-1)d)
2000=200+(n-1)20
n-1=(2000-200)/20
n-1=90
n=90+1=91

So, there are 91 terms in total