Please answer this one! Math function problem: F(t)= 90-521n(1+t), 0 <t<4?

Question

The function gives the number of units of the drug in the body after t hours.

What is the initial number of units of the drug administered?

How much is present after 2 hours?

Please help me with this one. Thank YOU!

Answer 1

initially, t=0, so F(0)=90

at t=2,   F(2)=90-ln(3)=32.872, approximately