Help with word problem

[lindsayvickroy]

I having been struggling with this word problem, can anyone help?

A diver leaps into the air at about 20ft per second from a diving board that is 10 ft above the water. For how many seconds is the diver at least 12 ft above the water?

I set it up as S= -16T^2+20T+10>12 and then I get confused.

Lindsay

 

[tkhunny]

-16T^2+20T+10>12

Try this: -16T^2 + 20T + 10 = 12
-16T^2 + 20T - 2 = 0
-8T^2 + 10T - 1 = 0
8T^2 - 10T + 1 = 0
Use the quadratic formula to find when the diver was at EXACTLT 12 ft. Subtract the lesser from the greater to get the total hang time over 12.

Note: I get about 1.031 sec