Since the amount if Caffeine decreases by 12% an hour, that is the same as a multiplier of 0.88 per hour.
r = ln 0.88 = -0.117833371
10 = 120 e^-0.117833371t
10/120 = e^-0.117833371t
0.8333 = 10/120
ln0.8333 = -2.48490665 so
e^-2.48490665 = e^-0.117833371t and so
-2.48490665 = -0.117833371t
-2.48490665/-0.117833371 = t
21.08830995 hrs = t
thus 21 hrs is your best answer.
Answer:
Step-by-step explanation:
As given ,
-5*(a+3) =-55
(-5*a)+(-5*3)= -55
-5a-15= -55
-5a= -55 +15
-5a = -40
a = 8
A. is 10! you multiply the scale (2.5) times the length (4)
b. is 6, you divide 15 by 2.5
c. is 5. you do what you did with a but with 2 inches instead of 4
d. is 1.5 you divide 378 by 250