A casserole is removed from a 375oF oven and cools to 190oF after 25 minutes in a room at 68oF. How long (from the time it is a removed from the oven) will it take the casserole to cool to 105oF

57.3 minutes

Step-by-step explanation:

We know that the temperature as a function of time of an object is described by the equation:

Where:

k is a constant

Tₐ =  room temperature = 68°F

T₀ =  initial temperature of the object = 375°F

Replacing these in our equation we will get

T(t) = 68°F + (375°F - 68°F)*e^{-k*t} = 68°F + (307°F)*e^{-k*t}

And we know that after 25 minutes, at t = 25min, the temperature of the casserole is 190°F

then:

T(25min) = 190°F = 68°F + (307°F)*e^{-k*25 min}

Now we can solve this for k:

190°F = 68°F + (307°F)*e^{-k*25 min}

190°F - 68°F = (307°F)*e^{-k*25 min}

(122°F)/(307°F) = e^{-k*25 min}

Now we can apply the natural logarithm in both sides:

Ln( 122/307) = Ln(e^{-k*25 min}) = -k*25min

Ln( 122/307)/(-25 min) = k = 0.0369 min^-1

Then the temperature equation is:

T(t) = 68°F + (307°F)*e^{-0.0369 min^-1*t}

Now we want to find the value of t such that:

T(t) = 105°F = 68°F + (307°F)*e^{-0.0369 min^-1*t}

We can solve this in the same way:

105°F - 68°F =  (307°F)*e^{-0.0369 min^-1*t}

37°F =  (307°F)*e^{-0.0369 min^-1*t}

(37°F)/(307°F) = e^{-0.0369 min^-1*t}

Ln( 37/307) = -0.0369 min^-1*t

Ln( 37/307)/( -0.0369 min^-1 ) = 57.3 min

So after 57.3 minutes, the temperature of the casserrole will be 105°F

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have

answer: 5100 just subtract

step-by-step explanation: