Answer:
First we need to see how many times 65% will make the price go up by 100%. We can see this by dividing 100 by 65. 100 divided by 65 is 1.53846153846. Now we can multiply 40 by 1.53846153846 and see what we get. 40x1.53846153846=$61.5384615384.
This is a lot of decibal numbers so if you seek more help then contact me on discord at Mousycritter#2842 for free advice!
Explanation: