Find the constant of variation k for the direct variation a) k=2.5 b) k=-2 c) k=2 d) k=0.5

Bismuth-210 is an isotope that radioactively decays by about 13% each day, meaning 13% of the remaining bismuth-210 transforms into another atom (polonium-210 in this case) each day. if you begin with 233 mg of bismuth-210, how much remains after 8 days?

The ratio of rock songs to dance songs on jonathan’s mp3 player is 5: 6. the total number of rock and dance songs jonathan has is between 101 120. how many rock songs does he have?

What is the ratio of the length of an object in yards to the length of the same object in miles?