To find when f(x)=g(x), then look for a value that is the same for both functions in the table. 0.25 occurs twice for the same x value. This is when they are equal. The solution is (1, 0.25).
Easy when rock is in water, it takes up a certain volume, say x so initial+x=final volume luckily we have final and inital 13.7ml+x=28.9ml minus 13.7ml both sides x=15.2ml
