Can someone me with these logic puzzles? i can't figure them out to save my

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.)

John read the first 114 pages of a novel, which was 3 pages less than 1/3 of the novel. write an equation to determine the total number of pages (p)(p) in the novel.

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50. write an inequality to determine the number of chores, c, janie could do to have enough money to buy the cd.