Answer:
- 12.5% -- Lenny's bug
- 10% -- Candice's board
- 15% -- Leo's bag
- 20% -- Josie's odometer
Explanation:
A percentage error is computed as ...
percent error = (amount of error)/(correct amount) × 100%
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Leo's bag: 1.5 lbs/(10 lbs) = 15%
Candice's board: 1.2 ft/(12 ft) = 10%
Lenny's bug: 2 cm/(16 cm) = 12.5%
Josie's odometer: 4 mi/(20 mi) = 20%
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There's nothing magical about percentages. They're just another way to write a number, usually a fraction. You can think of "percent" (%) as another way to write "divided by 100" or "hundredths" (/100). (In similar fashion, the symbol ‰ means /1000.)
1.5/10 = 15/100 = 15% . . . . fifteen hundredths is fifteen percent
1.5/10 = 0.15 = 15% . . . . . . fifteen hundredths is fifteen percent
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100% = 100/100 = 1, one full amount. A lot of times you will hear or see "multiply by 100 to change it to a percent." That is not true. Multiplying a number by 100 makes it be 100 times as big. When changing a number to a percent, you want it to keep its same value. That is why I show the fraction being multiplied by 100%. It is multiplication by 1, so the value stays the same.