Multiply the rate (44 ft per sec) by the number of seconds (35) to get 44*35 = 1540
The answer will be negative to indicate that the altitude has gone down. If you put in a positive change, then the altitude would go up. So that's why the answer is choice A
Note: when you multiply 44 ft/sec by 35 sec, the "second" units cancel out leaving just feet.
Another note: if you want, think of the 44 as -44 to indicate that the plane is decreasing at a rate of 44 ft/sec
To calculate the volume of a prism you multiply the area of it's cross section by the length
Therefore
5 x 3= 15
(Area of the rectangle)
15x8= 120
(Volume of prism)
if you go from 28 to 21 you see there is a difference of 7 and sense the number is a smaller number now we know the dolphin went up more towards the surface there for there is a change of positive 7
