Question

Find n(A) for the set.

1) A = 200, 201,
202, ..., 2000)
A) n(A)= 1801
B) n(A)= 4
C) n(A)=2000

Answer 1

A=200,201,202.........,2000

Here, it forms an AP with common difference 1

Let the number of terms in the set be n

`T_(n) = a+(n-1)d \\\\ 2000= 200+(n-1) \\\\ 200+n-1= 2000 \\\\ => n=2000-199= 1801`

Hence,n(A)=1801