Bob bikes to school every day at a steady rate of d miles per hour. On a particular day, Bob had a flat tire exactly halfway to school. He immediately started walking to school at a steady pace of y miles per hour. He arrived at school exactly t hours after leaving his home. How many miles is it from the school to Bob's home?
Choose one:
A) (d + y) / t	B) 2(d + t) / dy	C) 2dyt / (d + y)	D) 2(d + y + t) / dy	E) x(y + t) + y(x + t)
If we choose for d (distance): 10 miles, for d 10 and for y 5.   t would be 90 minutes or 1,5 hours.   If I try this for answer choice 2dyt / (d + y) it fits.
<result>C</result>
Bob bikes to school every day at a steady rate of d miles per hour. On a particular day, Bob had a flat tire exactly halfway to school. He immediately started walking to school at a steady pace of y miles per hour. He arrived at school exactly t hours after leaving his home. How many miles is it from the school to Bob's home?