A pot of boiling soup with an internal temperature of 100 degree F was taken off the solve to cool in a 69 degree F room. After 15 mintues the internal temperature of the soup was 95 degree F. To the nearest minute, how long will it take the soup to cool to 80degree F?

86.34 min

Step-by-step explanation:

Using the formula for Newton's law of cooling.

where T₀ = initial temperature of object = 100 F

T₁ = temperature of surrounding = 69 F

T = final temperature of object and

t = time

Initially, when the temperature of the soup drops to 95 F, it takes 15 minutes. So, T = 95 F and t = 15 min

Substituting all the variables into the equation for T we have

So,

When T = 80 F,

So, it takes the soup 86.34 minutes to cool to 80 °F

5   1/4   miles per hour

step-by-step explanation:

15   3/4 / 3 = 5   1/4