Answer:
∴35.97 mg caffeine would be left in the system after 5 hours.
Step-by-step explanation:
Given that,
A cup of coffee has approximately 310 mg of caffeine.
Caffeine decrease at a rate 35% per hour.
Exponential Function:

y(t)= Amount caffeine after t hours
= Initial amount of caffeine
r= rate of decrease
t = Time in hour.
Here y(t)=?,
= 310 mg, r=35%=0.35, t= 5 hours

=35.97 mg
∴35.97 mg caffeine would be left in the system after 5 hours.
2(3x - 4) = 5x + 20
6x - 8 = 5x + 20
subtract 5x from both sides
x - 8 = 20
add 8 to both sides
x = 28
Answer:
139.888 $
Step-by-step explanation:
Data :
15 ft = 24.98$
So
1 yard = 3 ft
15ft / 3 ft = 5 yard
So
5 yard = 24.98$
28 yd / 5yd = 5.6
5.6 × 24.98 = 139.888