Algebra help please!!

Colby and jaquan are growing bacteria in an experiment in a laboratory. colby starts with 50 bacteria in his culture and the number of bacteria doubles every 2 hours. jaquan starts with 80 of a different type of bacteria that doubles every 3 hours. let x equal number of days. colbys experiment follows the model: a.) y=50*2^x b.) y=50*2^8x c.) y=50*2^12x jaquans experiment follows the model: a.)80*2^x b.)80*2^8x c.)80*2^12x

Linda loans her friend $250 with a 5% monthly intrest rate. how much was the whole loan?

Susie wants to take her friend out for lunch.she wants to spend $9.75 each person. how much will she spend in all.