Help me find what b & c equals please

Initially 100 milligrams of a radioactive substance was present. after 6 hours the mass had decreased by 4%. if the rate of decay is proportional to the amount of the substance present at time t, find the amount remaining after 24 hours. (round your answer to one decimal place.)

Find the solution of system of equation y= x-4 y=4x+2

Tom travels between the two mile markers shown and then finds his average speed in miles per hour. select the three equations that represent this situation.