Answer:
given
n=9
a=1
d=3-1=2
Step-by-step explanation:
now , by formula,
sn = n/2(2a+(n-1)d)
= 9/2(2×1+(9-1)×2)
=9/2×18
=81
The answer for the question is a
You would set it up: .5/100 = x/490 and then cross multiply .5 time 490 and 100 times x, and end up with: 245=100x. divide by 100, and get 2.45
I think it is D
I am not sure but this is what I think it is