Fifty 6th grade students chose to play outside for free time. This is 25% of the 6th grade class. How many total students are there in the 6th grade?

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?

It says factor each expression 49x-28?

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?