Bob bikes to school every day at a steady rate of x 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?
a) (x + y) / t
b) 2(x + t) / xy
c) 2xyt / (x + y)
d) 2(x + y + t) / xy
e) x(y + t) + y(x + t)