Without seeing the graph, it's impossible to tell. The same can be said if we don't know the function rule. However, we can rule out three non-answers.
Choice B is false because the interval [1,3] has f(x) below zero but the rest of the interval to the right of x = 3 has f(x) not below zero.
Choice C is false. The value x = -1 leads to f(x) = 0 which is not greater than 0
Choice D is false because the values 8 and 4 are positive
After eliminating B, C, & D, we are left with choice A as the answer.
M represents the month because the value is decreasing every month.
Hope this helps :)
Answer: 384
There are 384 smoke free rooms.
5 minutes x minutes
--------------- = -------------
4 dishes 24 dishes
using cross products
5 * 24 = 4 * x
divide each side by 4
5*24/4 = x
30=x
It will take 30 minutes