Physics Web Assign Ch 14 #7

At rest, a car's horn sounds the note A (440 Hz). The horn is sounded while the car is moving down the street. A bicyclist moving in the same direction with one-third the car's speed hears a frequency of 413 Hz.
(a) Is the cyclist ahead of or behind the car?
-behind
-ahead

(b) What is the speed of the car?
_____ m/s

[stephanierich]

How in the world did you get -266.33 on the bottom of that equation? because 440-413=27 1/3 of 27 is 9.

[lilianwang]

Why is this negative 1/3 instead of 1/3? And at the end you neglect the minus sign.

[trishamehta]

trying to get rid of the fraction in this case just makes it more confusing than it needs to be