If you eliminate the parentheses, then add mq, you have
... y - p + mq = mx
Then dividing by m gives you the equation for x:
... x = (y - p + mq)/m
3/5 = 6/10 (which is 60%) 100% - 60% = 40%
125 MPH = 125/60 MP(Minute) because 1 Hour = 60 Minutes
= 2.0833...Miles per minute