Compute the unit rate. Choose all that are correct.
1 2 mile in each 1 4 hour is a rate of 1 8 miles per hour.
1 2 mile in each 1 8 hour is a rate of 4 miles per hour.
1 5 mile in each 1 10 hour is a rate of 2 miles per hour.
1 2 mile in each 1 6 hour is a rate of 1 over 12 miles per hour.