Problema Solution
Paul drove to the city, 200 miles away, and then returned home at speed which was 10 miles per hour faster than his trip to the city. If his trip to the city was 1 hour longer than his return trip, what was Paul's speed from home to the city?
Answer provided by our tutors
Distance = 200 miles
speed for going to city = x mp
returning speed = x+10 mph
Time to go to the city= Distance /speed = 200/x
Time for returning from to the city= Distance /speed = 200/(x+10)
200/(x+10) =(200/x) +1
Multiplying throughout by x(x+10),
{x(x+10)}{200/(x+10)} ={x(x+10)}{(200/x) +1}
i.e (x+50)(x−40)=0
x+50 =0 i.e. x= −50 mph
or x−40=0 i.e x= 40 mph
Since speed can not be negative x= 40 mph