Answer: 1/625
Given:
[tex]B=5^{-0.01t}[/tex]To find what fractional part of the batter is still operating after 400 hours of use, we just need to substitute t = 400 to the given equation.
[tex]B=5^{-0.01t}[/tex][tex]B=5^{-0.01(400)}[/tex][tex]B=0.0016\text{ or }\frac{1}{625}[/tex]Therefore, a fractional part of 0.0016 of 1/625 of the batter is still operating after 400 hours of use.
