Answer:
It will take 4 minutes and 30 seconds for hot coffee to cool to a temperature of 25 ° C
Step-by-step explanation:
This problem can be modeled by a first order equation
T(t) = TA + kt
In which TA is the temperature at instant zero and r is the rate of warming(g>0) or cooling(k<0). t is the time in minutes.
The initial temperature of the cup of coffee is 70ºC. So TA = 70. The temperature cools at the rate of 10ºC per minute, so k = -10. So, the equation of the model is:
T(t) = 70 - 10t
We want to know the instant of time when T = 25, so:
25 = 70 - 10t
10t = 70 - 25
10t = 45
t = 4.5 minutes
It will take 4 minutes and 30 seconds for hot coffee to cool to a temperature of 25 ° C
Answer:
point form: (1,-2)
Equation Form: x = 1, y = -2
Step-by-step explanation:
Answer:
15x + 15° = 3x + 9° + 78° (exterior angle is equal to the sum of the opposite interior angles)
15x - 3x = 9° + 78° - 15 °
12x = 72°
12x÷12 = 72°÷12
x = 6
Step-by-step explanation:
Ryan had a head start of 10 meters.
