Answer:
Cassie is traveling 63.6 mph
Step-by-step explanation:
If the three numbers, left to right, are A, B, C, then the tire radius in millimeters is ...
A×B/100 + 12.7×C
For the factory tires, the tire radius is ...
240·75/100 + 12.7·16 = 180 +203.2 = 383.2 . . . . millimeters
For the replacement tires, the tire radius is ...
290·70/100 +203.2 = 406.2 . . . . millimeters
The speedometer is calibrated based on the number of revolutions the tire makes in a given time period. If the truck goes farther for each revolution, its speed is higher by the same proportion.
If the speedometer on the truck with these replacement tires reads 60 mph, the actual speed is ...
(406.2/383.2)×60 mph = 63.6 mph
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<em>Comment on the problem statement</em>
<u>Caroline</u>'s truck has the replacement tires. If <u>Cassie</u>'s speedometer reads 60 mph, we have no reason to assume Cassie is traveling at any speed other than 60 mph.
