Time taken by Ria to paint a room = 4 hours
Time taken by Destiny to paint a room = 6 hours
If they work together, they complete 1 job. So,

The LCD of 4 and 6 is 12




Hence, both of them can paint the room in
hours or 2.4 hours.
A) you just do 2^9 which is 512 cubic millimeters
b) using the average rate of change formula you get 56.78 cubic millimeters per month
c) I do not understand at all I am stuck on the same one<span />
The question doesn't make a lot of sense, but I think the answer is $0.25, because In the equation b=0.25t, each text costs 25 cents