Question

21. If the nth term of an AP is (2n + 1), then
the sum of its first three terms is
(a) 6n +3 (6) 15
(c) 12 (d) 21​

Answer 1

Answer:

15

Step-by-step explanation:

Given- nth term= 2n+1

so, 1st term=2×1+1=3

2nd term=2×2+1=5

3rd term =2×3+1=7.

So, now 3+5+7=15