Hi All,
While much of the work that is involved in this prompt is calculation-based (using the Distance Formula), the distance IS a variable, so we can TEST VALUES to get to the correct answer.
We're told that each "leg" of a bicycle tour is the same distance and the speed on each of the legs is 16km/hr, 24km/hr and X km/hr. We're asked what that third speed much be to make the AVERAGE SPEED for the ENTIRE tour 24km/hr.
IF....
Each leg = 24km
The ENTIRE tour is 72 km; an average speed of 24km/hr means that the entire tripe must be...
72km = (24km/hr)(Total Time)
72/24 = Total Time
3 hours = Total Time
1st leg --> 24km = (16km/hr)(T)
24/16 = T
1.5 hours = T
2nd leg --> 24km = (24km/hr)(T)
24/24 = T
1 hour = T
With 2.5 hours spend on the first two legs of the tour, this gives us 1/2 hour for the final leg of the tour:
3rd leg --> 24km = (X km/hr)(1/2 hour)
24/(1/2) = X
48 km/hr = X
So the speed of the 3rd leg must be 48 km/hr.
Final Answer:
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Rich
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