Question 535084: Lisa traveled to her cabin on the lake and back. the trip there took five hours and the trip back took 6 hours. she averaged 45 km/h on the return trip. what was her speed for the trip there?
Found 2 solutions by josmiceli, lmeeks54:
Answer by josmiceli(19441)   (Show Source):
Answer by lmeeks54(111)  (Show Source):
You can put this solution on YOUR website! The key to problems such as this is to understand the basic formulas linking time, distance, and rate (speed). For this problem, d = distance traveled in km, t = time traveled in hrs, and r = the rate of travel in km/hr. The basic formula is: d = r * t, which could also be: t = d / r or r = d / t
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Lisa made two trips of identical distance (a safe assumption for math problems in class, but not necessarily a safe assumption in real life since Lisa could have driven two different routes). So, we can use data and calculations from one trip to help figure out the other trip.
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Trip 1:
d = unknown, r = unknown, t = 5 hrs
Trip 2:
d = unknown, r = 45 km/hr, t = 6 hrs
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Trip 2, calculate for d: d = r * t = 45 km/hr * 6 hrs = 270 km
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Take this result back to Trip 1:
d = 270 km, r = unknown, t = 5 hrs; solve for r: r = d / t = 270 / 5 = 54 km/hr
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54 km/hr is the answer to problem.
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cheers,
Lee
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