At the start of a basketball game, the referee tosses a ball into the air for the jump ball. The equation that models the height of the ball is h(t) = -16t^2 + 30t + 8. During what time interval is the height of the ball above 10 feet? (Round your answer to the nearest tenth of a second.)
a)
Between 1.1 and 1.6 seconds
b)
Between 0.3 and 2.1 seconds
c)
Between 0.1 and 1.8 seconds

Question

At the start of a basketball game, the referee tosses a ball into the air for the jump ball. The equation that models the height of the ball is h(t) = -16t^2 + 30t + 8. During what time interval is the height of the ball above 10 feet? (Round your answer to the nearest tenth of a second.)
	a)	
Between 1.1 and 1.6 seconds
	b)	
Between 0.3 and 2.1 seconds
	c)	
Between 0.1 and 1.8 seconds

anonymous · Answer

i guess we have to solve 
$$-16t^2 + 30t + 8\geq 10$$

anonymous · Answer

or maybe 
$$16t^2-30t-8\leq -10$$
$$16t^2-30t+2\leq 0$$ 
$$8t^2-15t+1\leq 0$$ and now the quadratic formula to find the zeros 
you answer will be between them

anonymous · Answer

ooops i made a mistake 
$$16t^2-30t-2\leq 0$$
$$8t^2-15t-1\leq 0$$ that is better

anonymous · Answer

i messed this up somehow, answer is $.069<t< 1.8$