If, Then formula

Hello,

I am creating a spreadsheet for the company airplane. Part of it is to calculate how many of the miles flown were "occupied" (had passengers). I need to do this for each leg of the flight.

so leg 1 had 300 miles and 2 passengers. Occupied miles would be 300*2=600.
However, if there were no passengers, than the occupied miles is equal to the miles in the leg, or 300.

I need says if passengers is 0 than occupied miles = leg miles but if passengers is greater than 0 than multiply the leg miles by the passengers.

If anyone knows of a way to do this I would be so grateful.
Thank you!