When you plug y into the original equations, it comes out that the two numbers are 6 and 25. You can check your work because 6+25 = 31 and 6*25 = 150.
500=350(1+0.04/12)^12x
Solve for x
500/350=(1+0.04/12)^12x
X=(Log(500/350)/log(1+0.04/12))/12
X=9 months
P (Jack) = 4 / 52 = 1/13
P(Queen) = 4/52 =1/13
P(jack or queen) = 1/13 + 1/13 = 2/13
She's used 7/12 of the carton. Let me know if you want to see the work :)