Question

Solve! The formula for the nth term b of a geometric series is b=ar to the power of n-1. Find n when b=1024, a= 16, and r=2.
Choices are a. 5, b. 6, and c. 7

Answer 1

$b=ar^{n-1}\\\\b=1024=2^{10};\ a=16=2^4;\ r=2;\ n=?\\\\subtitute\\\\2^4\cdot2^{n-1}=2^{10}\ \ \ |use\ a^n\cdot a^m=a^{n+m}\\\\2^{4+n-1}=2^{10}\\\\2^{n+3}=2^{10}\iff n+3=10\ \ \ \ |subtract\ 3\ from\ both\ sides\\\\\boxed{n=7}\to\boxed{c.}$

Answer 2

Answer:

C. 7

Step-by-step explanation:

I used this answer and got it right