Final answer:
Kathy's speed is calculated by dividing the distance she ran (117 meters) by the time it took (15 seconds), resulting in a speed of 7.8 m/s, which makes option c) the correct answer.
Step-by-step explanation:
If Kathy can run 117 meters in 15 seconds, the way to find her speed is by dividing the distance (117 meters) by the time (15 seconds). This yields 7.8 m/s, which represents her average speed during that run. So the correct option is c) 7.8 m/s. To further elaborate, an Olympic-quality sprinter running 100 meters in 10 seconds has a speed of 10 m/s because 100 divided by 10 equals 10, and meters divided by seconds equals meters per second (m/s). Using that principle, we can check that our answer is reasonable by comparing it to the known speed of an Olympic sprinter. Kathy's speed is slightly lower, which seems logical given the context.
Speed calculations often involve unit conversions, and it's important to use the correct conversion factors. However, in this case, we're already using compatible units, meters and seconds, so no conversion is necessary. Thus, option c) 7.8 m/s is the correct calculation for speed.
To calculate speed, you divide the distance traveled by the time taken. In this case, Kathy's speed is calculated as follows:
Speed = Distance / Time
Speed = 117 meters / 15 seconds
Speed = 7.8 meters per second (m/s)
So, the correct answer is c) 7.8 m/s. Options a) and b) provide incorrect calculations or misinterpretations, and option d) presents an incorrect and significantly smaller value for the speed.