Hi can anybody help me with exponential distribution?

The speed of wind can be modelled with an exponential distribution with a mean of 40 miles per hour.

At a random location what is the probability that wind speed is less than 25 miles per hour?

What is the probability at a random location wind speed will exceed 100 miles an hour?

Now i know that this can be modelled as lamda e^(-lamda x)

and i also know that in that equation that lamda can be replaced by 1/40 (i think!) But i'm not sure how to work out the question. Can anybody give me a hand?