Geometry Question?

longitude is a measurement of position around the equator of earth. Longitude is measured in degrees,minutes,and seconds. Each degree contains 60 minutes and each minute contains 60 seconds. Minutes are indicated by the symbol ' and seconds are indicated by the symbol ''. williamsburg, VA, is located at 76degrees42'25''. Roanoke, VA is located at 79degrees57'30''. Find the difference of their longitudes in degrees minutes and, seconds.