Answer:
t ≥ 158.33, or rounded, t ≥ 160.
Step-by-step explanation:
The equation we're given is
W = -0.414t + 129.549, which an be written as
-0.414t + 129.549 = W.
We are asked to find the amount of time it would take for the water level to be less than or equal to 64 cups. Plugging this information in, we have:
-0.414t + 129.549 ≤ 64
To solve this, we first cancel 129.549 by subtracting from both sides:
-0.414t + 129.549 - 129.549 ≤ 64 - 129.549
-0.414t ≤ -65.549
Now divide both sides by -0.414:
-0.414t/-0.414 ≤ -65.549/-0.414
t ≥ 158.33
(When we multiply or divide both sides of an inequality by a negative number, we must flip the inequality symbol)