Can someone help with all three plz?

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.)

Abiologist is recording the loss of fish in a pond. he notes the number of fish, f, in the pond on june 1. on july 1 there were 63 fish in the pond, which is 52 fewer fish than were in the pond on june 1. which equation represents this situation? a. f – 52 = 63 b. f – 63 = 52 c. 63 – f = 52 d. f – 63 = –52

You earn a 12% commission for every car you sell. how much is your commission if you sell a $23,000 car?