A plane left Kennedy airport on Tuesday morning for an 630mile 5 hour trip for the first part of the trip the average speed was 120 mph for

Question

A plane left Kennedy airport on Tuesday morning for an 630mile 5 hour trip for the first part of the trip the average speed was 120 mph for the remainder of the trip the average speed was 130 mph how long did the plane fly at each speed

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Dulcie 3 years 2021-08-30T12:18:32+00:00 1 Answers 16 views 0

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  1. ngockhue
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    2021-08-30T12:20:17+00:00
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    Answer:

    The plane travelled for \text{$2$ hours} at an average of speed 120\; \rm mph and \text{$3$ hours} at an average speed of 130\; \rm mph.

    Step-by-step explanation:

    Let x denote the number of hours that the plane travelled at an average speed of 120\; \rm mph.

    Given that the trip is 5\; \text{hours} long in total, the plane would have travelled at an average speed of 130\; \rm mph for (5 - x)\; \text{hours}.

    The plane would have travelled 120\, x miles after x\; \text{hours} at an average speed of 120\; \rm mph. Likewise, the plane would have travelled 130\, (5 - x)\; \text{miles} after (5 - x)\; \text{hours} at an average of 130\; \text{mph}.

    The plane has travelled 630\; \text{miles} in total. In other words:

    120\, x + 130\, (5 - x) = 630.

    Solve this equation for x: x = 2.

    In other words, the plane has travelled for \text{$2$ hours} at an average of speed 120\; \text{mph}. It would have travelled for (5 - x)\; \text{hours} = (5 - 2)\; \text{hours} = 3 \; \text{hours} for the other part of the trip (at an average speed of 130\; \text{mph}.)

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