Pls help me with this question!!!

There a total of 82 students in the robotics club and the science club. the science club has 6 fewer students than the robotic club. how many students are in science club?

Next, chad created this graph with ordered pairs that show the possible ratios of the number of damage to defense cards in his deck.what error chad make?

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.)