Question

Please give me the correct answer.Only answer if you're very good at math.​

Answer 1

10

Explanation:

How many coupons did we each earn just for arriving at Castel Saint'Angelo? This represents the initial value in this situation.

If you look at the graph, before we went to any monuments (when monuments=0), we already had 10 coupons. Thus, the initial value is 10 coupons.