Write 11/12 demoniator 84 to a equivalent fraction​

Hi my sisters and brothers can tell me the answer because i don’t understand the question

Jack did 3/5 of all problems on his weekend homework before sunday. on sunday he solved 1/3 of what was left and the last 4 problems. how many problems were assigned for the weekend?

Which of the following is the maximum value of the equation y=-x^2+2x+5 a. 5 b. 6 c. 2. d. 1