So hmmm check the graph below
now.. to find the vertex of any quadratic

so... how long did it take? well, it took

what was the highest point? well, it was

when did he hit the water? well, at y = 0
that is

solve for "t"
5 units (extra characters......)
The number of new calculators tested was 50 . . . 8 were bad and 42 were good.
The ratio of defective ones to new ones tested is 8:50 or 4:25 or 16% .
I think it might be B.. but i’m not sure bc I would think it would be amen who prefer dance