Apatient is given a 100-milligram dosage of a drug that decays exponentially at a rate of 11% per hour. which equation could be used to find the time when 15 milligrams of the drug remain?

a. 100 = 15(0.89)^x
b. 100 = 15(0.11)^x
c. 15 = 100(0.89)^x
d. 15 100(0.11)^x

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?