Final answer:
The equation y = 10x + 40 matches Option A, which is the cost of a product with a $40 base price and a $10 increase per unit, and Option C, which is the temperature of a substance increasing by 10 degrees Celsius per hour.
Step-by-step explanation:
The equation y = 10x + 40 represents a linear relationship where y is the dependent variable and x is the independent variable; the coefficient '10' represents the rate of change per unit increase in x, and '40' is the y-intercept, representing the starting value of y when x is zero. Analyzing the given options:
Option A: The cost of a product with a $40 base price and a $10 increase per unit clearly fits the equation, as the base price (y-intercept) is $40 and the cost increases by $10 for each additional unit (slope).
Option B: The distance traveled in 10 minutes at a speed of 40 km/h does not fit the equation because the distance would be a constant 40 km/h multiplied by the time in hours, which is not represented by this equation.
Option C: The temperature of a substance increasing by 10 degrees Celsius per hour fits the model as the base temperature would start at 40 degrees and increase by 10 degrees each hour.
Option D: This describes a direct relationship between the number of books read and the total cost, not the cost per unit, therefore it does not fit the equation.
Therefore, the situations that could be represented by the equation y = 10x + 40 are Option A and Option C.