An illustration of a ringing bell and dots representing air molecules. The dots are close together, then far apart and close together again representing a longitudinal mechanical wave of sound going from the bell to an ear.
How many wavelengths are seen in this image of a sound wave?

three
four
six
ten

the expression 15n + 2(3p) represents the amount isaiah spent buying gasoline and snacks, where n represents the price of each gallon of gasoline and p represents the cost of each snack that he bought. which statement is true about the amount isaiah spent?

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray