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Hint |
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1) Markus is on his school's swim team and is working to improve his lap time. On January 31st, his average lap time was 31.23 seconds. If Markus improves his average by 10% every month, what
should his average lap time be on May 31st? (Round your answer to the nearest hundredth of a second)
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- After every month his average lap time goes down by 10%, so that is a multiplication of each month's lap time by _____.
- There are 4 months over which his lap time improved so his lap time after 4 months his lap time was:
= ____________ seconds.
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2) Carrie took a train that travels at 70 mph from home to work. The train she took for the return trip traveled at 90 mph. What was her average speed for the round trip?
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Note: The answer is NOT (70+90)/2 = 80 mph!
You must compute the times for each leg of the trip and divide the total distance by that time.
- Assume a trip length that's easy to compute with: 10 miles.
- The time for the trip to work was:
_______ hour
- The time for the trip back home was:
_________ hour
- Total round trip time =
________________ hour.
- The average speed was _____________
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3) If you take a cube and shrink each length by a factor of 3, what is ratio of the final volume to the
initial volume?
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The cube's volume is reduced by (_____)3 = __________
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