what is the answer ?

Question

Brian places a bottle of water inside a cooler. As the water cools, its temperature Ct

 in degrees Celsius is given by the following function, where t

 is the number of minutes since the bottle was placed in the cooler.

=Ct+911e−0.028t

Brian wants to drink the water when it reaches a temperature of 14

 degrees Celsius. How many minutes should he leave it in the cooler? 

Round your answer to the nearest tenth, and do not round any intermediate computations. 

Answer 1

Answer:

C(t) = 9 + 11e^-.028t

14 = 9 + 11e^-.028t

^{5 = 11ln} e^-.028t

^{5/11 =} e^-.028t

^{ln 5/11 = -.028t}

^{t = (ln 5/11)/-.028t}

^

^{t=28.2 C}