This question has to do with speed and sound

Question

Jimmy wakes up late for school. Fortunately, his house is near to the school property, so he doesn’t have far to go. In fact, his bedroom window is exactly 260 m from the wall of the school gym. As he is packing his school bag, he remembers that his gym teacher only makes them run outside if the temperature is over 10°C. Remembering what he learned in Physics class, Jimmy opens his window and claps loudly, hearing the echo of his clap 1.55 s later. Does Jimmy need to take his running gear to school?

Answer 1

I will assume you use the speed of sound to be 343 m/s at 20 Celsius and it reduces by 0.6 m/s for each degree drop.

The echo takes 1.55 seconds so the one way trip is 0.775 s. If the gym is 260 meters away, the speed of sound on that day is 335.5 m/s

To determine the temperature we use 335.5 = 343 - 0.6 * Temp Drop

Temp Drop = 12.5 degrees which means the outdoor temp is 7.5 Celsius so he does not need to run