9514 1404 393
Answer:
216 mi/h
Step-by-step explanation:
The time for the trip with the wind is ...
(1080 mi)/(225 +45 mi/h) = 4 h
The time for the trip against the wind is ...
(1080 mi)/(225 -45 mi/h) = 6 h
The average speed for the entire round trip is ...
(2160 mi)/(4 +6 h) = 216 mi/h
This is a proportion problem.
Let's make her Length x and her height 1/3 x.
1/3 x = 20 inches
x = 6 2/3 inches
Molly's height is 6 2/3 inches.
Check it.
6 2/3 x 3 = ? (change the mixed number to a fraction)
20/3 x 3 = ? (multiply)
60/3 = ? (divide)
20 inches. Yes, it checks.
