A scientist uses a submarine to study ocean life she begins at C level which is at an elevation of 0 feet then she travel straight down for 90 seconds at a speed of 3.5 ft./s then she then travels directly up for 30 seconds how do you speed of 2.2 ft./s after this 120 seconds period how much time in seconds will it take for the sciences to travel back to see if level at the submarines maximum speed of 4.8 ft./s

9514 1404 393

  10.625 seconds

Step-by-step explanation:

distance = speed · time

We want the total of all distances to be zero.

  (-3.5)(90) +(2.2)(120) +(4.8)t = 0

  -315 +264 +4.8t = 0 . . . . . simplify

  -51 +4.8t = 0 . . . . . . . . . . . simplify more

  -10.625 +t = 0 . . . . . . . . . .divide by 4.8

  t = 10.625 . . . . . . . . . . . . . add 10.625

It will take the scientist 10.625 seconds to reach sea level.

5x+2x=49

7x=49

x=7. 35 apples