Dont you thin some math question are kinda incomprehensible?

october4th
Sun, 18 Jan 2009 11:52:35 +0000

ignore k, plug 10 into t.

set .5t^2-20t equal to whatever you get.

multiply by two to get rid of the fraction.

set it equal to zero and solve.

you should get two solutions (10 and 30)