Answer:
The amount of drug left in his body at 7:00 pm is 315.7 mg.
Explanation:
First, we need to find the amount of drug in the body at 90 min by using the exponential decay equation:

Where:
λ: is the decay constant = 
: is the half-life of the drug = 3.5 h
N(t): is the quantity of the drug at time t
N₀: is the initial quantity
After 90 min and before he takes the other 200 mg pill, we have:

Now, at 7:00 pm we have:

Therefore, the amount of drug left in his body at 7:00 pm is 315.7 mg (from an initial amount of 400 mg).
I hope it helps you!
(3) Gamma has the greatest penetration power. Alpha has low and both beta and positron have medium. Hope I helped :)
Answer:
the axis is tilted at 98 degrees
Explanation:
Uranus is blue, not green; it has an atmosphere of hydrogen and helium, not methane. While it does have an icy cold temperature, that's not a very unusual characteristic for an outer planet. However, the tilt of the axis is unusual; no other planet is tilted almost completely on its side!
1.123 nano-grams is your answer, do you understand now gimme dat 5 star and brainiest