Answer:
hi
Step-by-step explanation:

i think so…
I believe it would be negative 9 because your subtracting by twelve again. I hope that helped
---<span>
y(t) = a*e^(kt)</span><span>
---
now:</span><span>
130 mg</span><span>
---
one hour from intake:</span><span>
130 * (1 - 0.11) = 115.7 mg</span><span>
---
y(1) = 115.7 = 130*e^(k(1))</span><span>
115.7 = 130*e^k</span><span>
115.7/130 = e^k</span><span>
ln( 115.7/130 ) = ln( e^k )</span><span>
ln( 115.7/130 ) = k</span><span>
k = -0.1165338
</span><span>---
three hours from intake:</span><span>
y(3) = 130*e^(3k)</span><span>
y(3) = 91.64597</span><span>
---
answer:</span><span>
three hours after drinking a cup of coffee, 91.6 mg of caffeine will remain in the body
</span>
There's an infinite number of ways we can rewrite 16 3/4, some of them being:
16 3/4
16 6/8
16 12/16
16 24/32
16.75
67/4
335/20
670/40
etc.
I hope it will help you ;)