I’m not sure what happened while you were writing this, but if I’m reading it right, “My” has 18 books. If “My” has 3 times as many as 6, that also means 3 times 6, which is 18.
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:
brainly.com/question/8893949
#LearnwithBrainly
Answer: 20.0 inches
Step-by-step explanation:
D, 8.5
a squared + b squared = c squared for the sides and hypotenuse of the triangle.
6^2 + 6^2 = c^2
36 + 36 = c^2
72 = c^2
c = square root of 72, 8.49