Step-by-step explanation:
i) Since it is for 1 day, and they only use it for 2 hours in a day,
3.5 * 2 = 7
So $7 dollars for one day
ii) Since it is for 1 week, and 2 hours each day, which means 7 days, that would be 7 * 2, which equals 14:
14 * 3.5 = 49
So $49 dollars for one week
iii) Since it is for December, and there are 31 days in December, that would be 31 * 2, which equals 62:
62 * 3.5 = 217
So, $217 dollars for all of December
:)