I would like to know how these 2 Doppler Effect exercises are done

A train travels at 30m/s in still air. The frequency of the note emitted by his whistle is 262 Hz. What frequency is heard by a passenger on a train moving in the opposite direction at 18 m/s and a) approaching to the first train b) Does it move away from it?

. Two identical tuning forks oscillate at 442 Hz. A person's ear is located at a point on the line that unites them Calculate the beat frequency heard by the individual if: a) he is stationary and the tuning forks are moving to the right at a constant speed of 31.3 m/s. b) The tuning forks are stationary and he is moving to the right at a constant speed of 31.3 m/s.