What is the unit rate of 60miles on 2.5 gallons

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?

Ab and bc form a right angle at point b. if a= (-3,-1) and b= (4,4) what is the equation of bc?

The midpoints of the sides of the large square are joined to form a smaller square. what is the area of the smaller square