Kinda stuck with this one

ok here's the problem i'm havin' a problem with getting the right solution

"When two chemicals, A and B react, 1 gram of A and 2 grams of B yield 2 grams of C and a by-product. The rate at which C is formed is proportional to the amount of A and B present. Sypose that at the outset there is 50 grams of A and 90 grams of B present, and that after 1 hour, 45 grams of C have been formed."

Show that the amount of C that has been formed after t hours

What is the maximum of C that can be obtained from this process?

i'm mainly having trouble with the first section but you need it for the second part, any help with this would be good