







Exponential decay 
20060329 

From Casey: Fifty milligrams of a drug was injected into a patient at 6am. The drug is known to be eliminated according to the law of exponential decay. At 8.30am it was determined that 60% of the drug remained in the body. How many milligrams will remain in the body at midday? Answered by Penny Nom. 





Prescription drug coverage 
20031204 

From Khadijah: Last week congressional approval was given to legislation involving prescription drug coverage for seniors. One summary of the legislation explains that it is estimated that in 2006 a senior will pay a premium of $35 per month, then pay their first $250 in pharmacy bills. After the bills reach $250, the coverage would pick up 75% of their bills that bring their total bills between the $250 and $2250 mark. After their bills reached a total of $2250, the senior would be responsible for all bills bringing their total annual bills between $2250 to $5100. Then any bills after the $5100 mark has been reached will be 95% covered by the insurance. Using this information, letís analyze the situation of a senior who accumulates $6000 in pharmacy bills over one year and has the insurance coverage. Over the course of this year, how many dollars will the senior pay? Answered by Penny Nom. 





R= 5.3lnx + x. 
20030511 

From A student: Reaction R to a dose x is given by: R= 5.3lnx + x. For a certain drug, R must not exceed 21. Show that a dose between 8 and 12 units satisfies this requirement & find, correct to 5 decimal places, the greates value of x which satisfies this condition? Answered by Harley Weston. 





The effectiveness of a drug 
20030422 

From A student: A certain drug is found to be effective 80% of the time. Find the probability of successful treatment in two out of four cases. Answered by Andrei Volodin. 

