I need help I don’t understand at all !

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

Apackage of orgainc strwberries costs $1.50 while there in season and $2.25 when not in season what the percent increase

Arace is 10 kilometers long. markers will be placed at the beginning and end of the race course and at each 500 meter mark. how many markers are needed to mark the course for the race?