At what point do the increasing and decreasing parts of the graphs in Part A intersect?

Aboat's value over time is given as the function f(x) and graphed below. use a(x) = 400(b)x + 0 as the parent function. which graph shows the boat's value increasing at a rate of 25% per year?

Can someone me with this problem i don't understand i need

Maria walks a round trip of 0.75 mile to school every day.how many miles will she walk in 4.5 days