Amule deer can run one over four of a mile in 25 seconds. at this rate, which expression can be used to determine how fast a mule deer runs in miles per hour?

The way we work this out is by working out the amount of lots of 25 seconds in an hour, and then multiply it by that 1/4 of an hour. 1 hour has 60 minutes, and each minute has 60 seconds, so 1 x 60 x 60 = 3600 = the number of seconds in an hour.
3600/25 = 144. Therefore there are 144 lots of 25 seconds in an hour. If the deer runs 1/4 a mile in 25 seconds, then we just have to do 144 x 1/4 and it will give us the answer.
144 x 1/4 = 36. Therefore the deer can run 36 miles per hour.
If you want to express this all in one equation, we can write it as:
((60 x 60)/25) x 1/4 = 36