If a small airplane travels 28 miles in 12 minuets how far will the plane travel in one hour

There are 60 minutes in 1 hour. You want to convert minutes to an hour by multiplying 60 minutes per hour and that will give you the

(28miles)/(12minutes) * (60minutes/1hour)
The minutes will cancel out so you are left with miles/hour

140 miles/hr

B. because the 7 represents "seven times", x represents "a number", 12 represents "plus twelve", and -4 represents "minus four"