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Example

Finding Speeds for Consecutive Trip Segments Using a Known Total Distance

Apply the distance, rate, and time problem-solving strategy to find two unknown speeds when a single traveler covers two consecutive segments at different uniform rates, with the segment distances adding up to a known total and the faster rate expressed as a multiple of the slower rate.

Problem: Hamilton drives from his home in Orange County to Las Vegas, a total distance of 255255 miles. He departs at 2:00 PM and drives on congested city freeways. At 4:00 PM the congestion clears and he drives through the desert at a speed 1.751.75 times his city speed. He arrives in Las Vegas at 6:30 PM. What was his speed during each part of the trip?

  1. Read and draw: Sketch the route from Home to Las Vegas with two arrows — one labeled "city driving" (2:00 PM to 4:00 PM) and one labeled "desert driving" (4:00 PM to 6:30 PM). The total distance between the two endpoints is 255255 miles. Create a rate–time–distance table.

  2. Identify: The driving speed for the city segment and the desert segment.

  3. Name: Let rr = the city driving speed in mph. Because the desert speed is 1.751.75 times as fast, it equals 1.75r1.75r. Convert the clock times to elapsed times: city driving lasts from 2:00 PM to 4:00 PM, which is 22 hours; desert driving lasts from 4:00 PM to 6:30 PM, which is 2.52.5 hours. Multiply rate by time to fill in the distance column:

Rate (mph)Time (hrs)Distance (miles)
Cityrr222r2r
Desert1.75r1.75r2.52.52.5(1.75r)2.5(1.75r)
255255
  1. Translate: The city distance plus the desert distance equals the total of 255255 miles:

2r+2.5(1.75r)=2552r + 2.5(1.75r) = 255

  1. Solve: Multiply 2.5×1.75=4.3752.5 \times 1.75 = 4.375:

2r+4.375r=2552r + 4.375r = 255

Combine like terms: 6.375r=2556.375r = 255. Divide both sides by 6.3756.375:

r=40r = 40

The city speed is 4040 mph. The desert speed is 1.75×40=701.75 \times 40 = 70 mph.

  1. Check: City: 40×2=8040 \times 2 = 80 miles. Desert: 70×2.5=17570 \times 2.5 = 175 miles. Total: 80+175=25580 + 175 = 255 miles. \checkmark

  2. Answer: Hamilton drove 4040 mph in the city and 7070 mph in the desert.

This example demonstrates the consecutive-segment scenario: a single traveler covers two parts of a trip at different uniform speeds, and the individual segment distances add up to a known total. Unlike the equal-distance and opposite-direction examples, here the two speeds are related by a multiplicative factor (1.75r1.75r rather than r+12r + 12), the elapsed times for each segment are determined by converting separate clock-time intervals to durations, and multiplying the decimal coefficients produces the term 4.375r4.375r. Combining like terms with decimal arithmetic yields 6.375r=2556.375r = 255, which is solved by a single division.

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Updated 2026-05-02

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