Answer:
0.25 hours
Explanation:
The equation for a linear function is given by:
y = mx + b,
where y and x are variables, m is the rate of change of y with respect to x and b is the initial value of y (value of y when x = 0).
Let x represent the number of hours after 1:00 P.M and let y represent the temperature in degree Fahrenheit.
Let us assume that initial the temperature is 0°F. The temperature changes -4 degrees Fahrenheit per hour. From the equation of a linear function y = mx + b:
m = -4 degrees Fahrenheit per hour, b = 0. Hence:
y = -4x
The time taken to reach -1°F is gotten by substituting y = -1 and finding x:
y = -4x
substituting:
-1 = -4x
x = -1 / -4
x = 0.25 hours
0.25 hours = 0.25 hours * 60 minute / 1 hour = 15 minute
Therefore at 1:15 P.M, the temperature is -1°F