The sister catches up Jeff after 2 hours
Step-by-step explanation:
We can write Jeff's position and his sister position at time t using the following expressions:
- Jeff position:
where:
7 is the initial position of Jeff when his sister sarts chasing him
2.5 is Jeff's velocity (in miles/hour), so its position increases by 2.5 miles for each hour
t is the time measured in hours
- Sister position:
where
6 is the sister velocity (her position increases by 6 miles for every hour)
t is the time measured in hours
The sister catches up Jeff when the two positions are equal, so
And solving for t,
So, the sister catches Jeff after 2 hours.
Learn more about speed:
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