Speed problems: The Speed Table - Handling Speed Problems with Data Overload
Lassie goes hunting. The dog chases a bird for 30 meters at 15 meters per second. Lassie does not catch the bird and immediately goes on to chase a cat for an additional 56 meters at 7 meters per second. What is Lassie's average speed for the entire hunt?
Incorrect.
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Incorrect.
[[snippet]]
Incorrect.
[[snippet]]
Incorrect.
[[snippet]]
Correct.
You cannot miss the fact that this is an "average speed question,"
but before applying the average speed formula, organize
the {color:dark-green}information in the question{/color} in a Speed table.
| | SPEED (M/SEC) | TIME (SEC) | DISTANCE (M) |
|------|-------------------------|---------------------|-------------------------|
| Bird | {color:dark-green}$$15$${/color} | $$\frac{30}{15}=2$$ | {color:dark-green}$$30$${/color} |
| Cat | {color:dark-green}$$7$${/color} | $$\frac{56}{7}=8$$ | {color:dark-green}$$56$${/color} |
| Total | | $$10$$ | $$86$$ |
Then use the average speed formula to calculate the answer:
>$$\displaystyle \text{Average speed}= \frac{86\ \text{meters}}{10\ \text{seconds}}=8.6\ \text{meters per second}$$
8
8.6
9.6
10.75
11
