SOLUTION: The distance from Lance’s home to his beach house is 80 miles. When biking back from his beach house to his home, his average speed was 20% slower than his average speed biking fr

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Question 1069156: The distance from Lance’s home to his beach house is 80 miles. When biking back
from his beach house to his home, his average speed was 20% slower than his average speed biking from his home to his beach house. If the roundtrip time was 9 hours, what was his average speed, in miles per hour, from the beach house to his home?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
                    SPEED      TIME          DISTANCE
HOME to BEACH        r         80/r            80
BEACH to HOME       r*(4/5)    80/(r(4/5))     80
Total                           9


80%2Fr%2B80%2F%28%284%2F5%29r%29=9

80%2Fr%2B80%2A5%2F%284r%29=9

80%2Fr%2B20%2A5%2Fr=9

180%2Fr=9

r=180%2F9

highlight%28r=20%29, speed from Home to Beach House.

Beach House to Home is 20% slower, 20%2A%280.8%29=highlight%2816%29.