Help please with these 2 equations (also we’re supposed to solve them using the elimination method I believe, and turn the picture the side idk why it’s sideways like that)

The half-life of a certain material is 0.004 second. approximately how much of a 20-gram sample will be left after 0.016 second? a. 5 grams b. 16 grams c. 0.32 gram d. 1.25 grams

Will mark brainiest, , and rate to the best the table shows the number of blue marbles and red marbles that four friends have collected. which person has the lowest ratio of blue to red marbles? jasmineaaronluciangretchen

Write the equation of a line that goes through point (0, 1) and has a slope of 0.