Answer:
51.9 seconds
Step-by-step explanation:
First I multiplied 90 seconds by 3.5 fps (feet per second) to figure out how deep she went. I got 315 feet.
Second I multiplied 30 seconds by 2.2 fps to figure out how far she went back up. I got 66 feet.
I then subtracted 66 from 315 to get 249 feet.
After that I divided 249 feet by 4.8 fps to figure out how long it took her to get back to sea level and got 51.875 seconds, which rounded to the nearest tenth, is 51.9 seconds.
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