math

posted by .

You jog at 6.6 mi/h for 5.0 mi, then you jump into a car and drive for another 5.0 mi. With what average speed must you drive if your average speed for the entire 10.0 miles is to be 10.4 mi/h?

answer is 24.5 mi/h.


WHY??

  • math -

    let the speed in the car be x mph

    so 5/6.6 + 5/x = 10/10.4
    5/x = 10/10.4 - 5/6.6
    5/x = .20396
    x = 5/.20396
    x = 24.5

    he should drive the last 5 miles at 24.5 mph

    check
    if avg speed is 10.4 mph, then it took
    10/10.4 hours or .9615 hours

    time jogging = 5/6.6 = .7576 hours
    time in car = 5/24.5 = .20408 hours
    for a total time of .96166 hours

    allowing for roundoff errors, close enough!

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Science - Physics

    How long would it take you to drive from Houston to Gatorville LA (235 miles0 if you drive the first 75 miles at 60 mph, the next 100 miles at 65 mph, and the last 60 miles at 70 mph?
  2. physics

    You jog at 6.0 mi/h for 5.0 mi, then you jump into a car and drive for another 5.0 mi. With what average speed must you drive if your average speed for the entire 10.0 miles is to be 10.0 mi/h?
  3. physics

    You jog at 6.0 mi/h for 5.0 mi, then you jump into a car and drive for another 5.0 mi. With what average speed must you drive if your average speed for the entire 10.0 miles is to be 10.0 mi/h?
  4. physics

    You jog at 6.0 mi/h for 5.0 mi, then you jump into a car and drive for another 5.0 mi. With what average speed must you drive if your average speed for the entire 10.0 miles is to be 10.0 mi/h?
  5. Physics

    To get to a concert on time, Dakota has to drive 122 miles in 2.00 hrs. (a) if he drove at an average speed of 55.0 mi/hr in a due west direction for the first 1.20 hr what must be his average speed if he is heading 30 degrees south …
  6. physics

    You jog at 6.2 mi/h for 5.0 mi, then you jump into a car and drive for another 5.0 mi. With what average speed must you drive if your average speed for the entire 10.0 miles is to be 10.6 mi/h?
  7. Physic Help

    In heavy rush-hour traffic in Atlanta, you drive in a straight line at 21 mph for 5 miles. Then you have to stop for 10 minutes and finally drive slowly by a car wreck that is 2 miles away at a steady 15 mph. After the wreck, the road …
  8. Math

    A woman went for a 48km drive in her car, partly in town in the country. She drove at an average of 40km/hr in town and an average speed of 50km/hr in the country. If the drive took her one hour altogether then how long did she drive …
  9. physics

    You jog at 9.5 km/h for 7.0km , then you jump into a car and drive an additional 16km . With what average speed must you drive your car if your average speed for the entire 23km is to be 22 km/h?
  10. math (pre calc)

    Imagine that you are driving 150 miles and you want your average speed for the trip to be 60 miles per hour.Imagine that you drive the first half (by distance) of the trip at 50 mph. How fast must you drive on the second half to make …

More Similar Questions