Question

The swimming pool is open when the high temperature is higher than 20°C. Lainey tried to swim on Monday and Thursday (which was 333 days later). The pool was open on Monday but closed on Thursday. Write an inequality to determine the rate of temperature decrease in degrees Celsius per day, d, from Monday to Thursday.

A) d > 0

B) d < 0

C) d = 0

Answer 1

The inequality to determine the rate of temperature decrease per day, d, is d < 0, indicating that the temperature was dropping over the period of 333 days. The correct option is B.

Step-by-step explanation:

The student is asking how to write an inequality to determine the rate of temperature decrease, d, over 333 days considering the swimming pool was open on Monday and closed on Thursday. Since the pool was open on Monday, we can assume the temperature was above 20°C, and as it was closed on Thursday, the temperature must have been at or below 20°C. If t represents the temperature on Monday, then after 333 days (by Thursday), the temperature t - 333d had to be ≤20°C.

Therefore, t - 333d ≤ 20. If t > 20 on Monday, then we can deduce d must be greater than 0 for the temperature to decrease. However, to meet the conditions given (that is, the temperature dropped below the threshold), d must be less than 0 to show a decrease. Thus, the inequality that represents the rate of temperature decrease per day would be d < 0.