24, because the volume of a cone with the same radius and height of a cylinder with the same dimensions is always 1/3 the volume of the cylinder.
So this is going to be an exponential equation, which the format is

, in which a is the initial value and b is the growth/decay rate.
In this case, a is going to be 340,000 and b is going to be 107%, or 1.07, since the population is going to be increasing by 7% and the equation is now

.
Now replace x with 12 and solve.

Solve

, and then if you don't round that answer and multiply it with 340000 you get

.
If two lines intersect, then there is only one solution - where they cross.
Looking at the graph, we can see the intersection point of these two lines.
The intersection point is (1,1) - one unit to the right of the origin and one unit up.
Hope this helps! :)
The unit rate is approximately 18 i think. Hope it helps :)