A cyclist rides 60 km. If she rode 5 km/h faster, the ride would take 1 hour less…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A cyclist rides . If she rode faster, the ride would take hour less. Find her usual speed.
Need a reminder? The key ideaShow
Name the unknown with its unit, write the equation, put it in standard form, factorise, and keep only the roots that make sense. Time distance speed. Lengths, speeds and ages cannot be negative.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Equation. .
Step 2. Clear the fractions. , so .
Step 3. Solve. , so .
Step 4. Meaning. A speed is positive: . Check: hours at and hours at both cover .
Answer: .
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