Apassword consists of 2 letters followed by 2 digits. how many different passwords can be formed?

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?

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

The length of each stair is 11 inches. what is the rise, r, for each stair? round to the nearest inch. 2 inches 7 inches 17 inches 24 inches