Answer:
29.88 inches
Step-by-step explanation:
Equation of a line is given in the form
Where
m is the slope [rate of change, here, rate of decrease]
c is the y-intercept [at 1920, the snowfall]
From the problem, we see that snowfall decreases by 0.24 inches per year, that will make the slope (m) to be -0.24
Also, at 1920, the initial measurement was 48.6 inches of snow, that is the y-intercept (b). Thus, we can write the equation of this line as:
y = mx + b
y = -0.24 x +48.6
To find annual snowfall, 78th year after 1920, we simply plug in 78 into "x" of the equation just found. So:
y = -0.24(78) + 48.6 = 29.88 inches
