Please tell me if my answers are right or wrong and how you got the right answer. A cylindrical tank with a cross-sectional area of 100 square cm is filled to a depth of 100 cm. At t=0, a drain in the bottom of the tank with an area of 10 square cm is opened allowing water to flow out of the tank. The depth of water in the tank at time t=0 is d(t) = (10 -2.2t)^2 a) Check that d(0) = 100 as specified. Yes, it's true. b) What is an appropriate domain for d? Depth cannot be lower than 0, and it started at 100, so 0

Question

Please tell me if my answers are right or wrong and how you got the right answer.
A cylindrical tank with a cross-sectional area of 100 square cm is filled to a depth of 100 cm. At t=0, a drain in the bottom of the tank with an area of 10 square cm is opened allowing water to flow out of the tank. The depth of water in the tank at time t>=0 is 
d(t) = (10 -2.2t)^2
a) Check that d(0) = 100 as specified.
Yes, it's true.
b) What is an appropriate domain for d?
Depth cannot be lower than 0, and it started at 100, so 0<d<100
c) At what time is the tank empty?
50/11

anonymous · Answer

fist two seem correct

anonymous · Answer

you're correct on all of them

anonymous · Answer

the domain for d(t) is all t in [0, 50/11]... your answer in part b is the range, that is, all the possible values for the depth is your range.

anonymous · Answer

Thanks! So it's between 50/11 and zero because you can't have a negative time and at 50/11 it's empty?

anonymous · Answer

But couldn't it be [0, infinity]? because the depth might reach zero but time can keep on going?