Alphonse donates a fair amount of money to various charities each year. He wants to know that his money is actually going to do the charity work, though. Suppose that 90% of the charities that he donates to are probably reputable and 10% are probably not. Also, suppose that 80% of the money that goes to the real charities ends up actually
being used
for the charity work, while 20% goes to administrative costs. If he donates the same amount to each charity, then what
percent probably goes to actual charity work?