Question

Q3. The formula to find sum of n
terms is:

a) a+(n - 1)d/2
b) n/2 [a + (n - 1)d]
c) na +[ (n - 1)/2] d
d) na + [n(n-1)/2] d​

Answer 1

Answer:

really I know but i am confused

Step-by-step explanation:

ans is b