A plane flies at 160 mph for the first and last half hour of a flight. It flies at a higher constant speed for the rest of the flight....?

A plane flies at 160 mph for the first and last half hour of a flight. It flies at a higher constant speed for the rest of the flight. The route is 2040 miles. The plane is 940 miles from the destination 2 hours before the end of the flight.

How many hours is the entire flight?

2 Answers

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  • RR
    Lv 7
    2 weeks ago

    0.5 hours from the end of the flight, it is 160/2 = 80 miles from at the destination.

    In the 1.5 hours before the end of the flight, it travels

    940- 80 = 860 miles.

    Speed for this section is 860/1.5 = 573.3 mph

    The total flight is

    1 hour @ 160 mph travelling 160 miles

    t hours @ 573.3 mph travelling 2040-160 = 1880 miles

    Total time = 1880/573.3 = 3.28 hours

    total time = 3.28 + 1.0

    = 4.28 hours

    = 4hours 17 minutes

  • alex
    Lv 7
    2 weeks ago

    higher constant speed = (940-80)/1.5 = 573 1/3 mph

    time = 1 +(2040-160-940)/(573 1/3) + 2 = 4.64 hours=4 hr 38min

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