1. The problem statement, all variables and given/known data I've got a doppler shift question about calculating the frequency heard by a receiver moving 5.0m/s towards a sound source that is emitting 3000Hz sound. I assumed speed of sound is 343 m/s for an air temperature of 20C. 2. Relevant equations Freceiver = Fsender((V + Vreceiver)/V) Where V is speed of sound in air 3. The attempt at a solution After calculating the sound I get 3000Hz x (348/343) Which equals 3000hz x 1.015 =3043.731....Hz If I round off to one or two significant digits like the problem states then I get 3000Hz. Which doesn't make sense. What am I missing here? Is there some rule the over rides significant digits for these types of answers?