Answer:
a. L = 0.5d + 34, and
b. "Never," or "can't be determined with the information provided."
Step-by-step explanation:
a. Write an equation for the water level, L, after d days.
L is water level, in feet. It is rising at a rate of 0.5 ft/day. The slope of an equation of a straight line (we know it is straight, since the rate of increase is a constant, 0.5 ft/day) would be:
y = mx + b
y = 0.5x + b
x is the number of days, which are set to "d," as per the instructions., and b is the water height at day 0, the start. In this case, the initial height is 34 feet. So the equation for predicting future water levels, L, is:
L = 0.5d + 34 [L = 0.5(ft/day)d + 34(ft)]
b. In how many days will the water level be 26 feet?
The question is asking how many days it will take for the water level to reach 26 feet. This is odd, since we are only told that the river is rising. No information was given about timing when the river may begin falling, not the rate at which that will occur. Based only on the way the question is written, the answer is "Never," or "can't be determined with the information provided."
If the question was phrased "In how many days will the water level reach 42 feet, we can use the equation to find d:
L = 0.5d + 34
42 = 0.5d + 34
0.5d = 8
d = 16 days
