AIPMT 2014 Physics and Chemistry Paper

A speeding motorcyclist sees traffic jam ahead o him. He slows down to 36‌km∕ hour. He finds that traffic has eased and a car moving ahead of him at 18‌km∕ hour is honking at a frequency of 1392 Hz. If the speeds of sound is 343m∕s, the frequency of the honk as heard by him will be :-