Problema Solution
Shara left Atlanta for vacation traveling at 51mph. Brady left after Sarah and traveled at 60mph trying to catch up. If it took Brady 4 hours to catch up with Sarah, how long was Sarah driving before Brady started?
Answer provided by our tutors
Let
x = the time that Sarah was driving before Bradly started
v1 = the speed of Sarah
v2 = the speed of Brady
After 4 hours since Brady started driving (at the moment of catching up)
v1*(x+4) = the distance that Sarah has passed
v2*4 = the same distance that Brady made
they are equal thus
51*(x+4) = 60*x
x = 68/3 = 22 hr 40 min
Sara was driving 22 hr 40 min before Brady started.