Why does the speed of sound depend on air temperature?

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?

The number of passengers who arrive at the platform of a subway station for the 10 am train is a random variable with a mean of 120 and a variance of 16. find the lower bound of the probability that there will be between 100 and 140 passengers (round off to second decimal place).

On average 8 bananas make up one pound. the price is four pounds for 5.00. you must buy 25 bananas.what is your cost?