Let x be the number for first wrong answers, y be the right.
w be the number for the second wrong answers, z be right.t be the number of left questions.
We have y=2x,z=16-w,y+z=3(x+w),t=50-x-y-w-z. cancel y we have x=16-4w=4(4-w),z=16-w.t=34-3x
we get x=4,y=8,w=3,z=13.t=22; x=8,y=16,w=2,z=14.t=10.
