power usage is measured in kilowatt-hours, kwh. after 7 a. m., the power usage on a college campus increases at a rate of 21% per hour. prior to 7 a. m., 15,040 kwh have been used. the university has a daily goal to keep their power usage less than or equal to 100,000 kwh.
which of the following inequalities can be used to determine the number of hours, t, after 7 a. m. when the power usage on campus will be less than or equal to 100,000?
a: 15,040(1.021)t ≤ 100,000
b: 15,040(0.79)t ≤ 100,000
c: 15,040(1.21)t ≤ 100,000
d: 15,040(1.79)t ≤ 100,000