I need help I don’t get it help help

This question awards 100 ! i really don’t want to fail i will also mark you !

Equation for the calculation double 2 and then add 5

The price of a visit to the dentist is calculated according to the formula 50+100n50+100n where nn is the number of cavities the dentist finds. on your last visit to the dentist, 22 cavities were found. what was the cost of your visit?