nearest tenth please

Question

A ball is thrown upward from a height of 15 feet with an initial upward velocity of 5 feet per second. Use the formula b(t)= -16t² + 5t + 15 to find the time it takes for the ball to reach the maximum height of the ball. Round to the nearest tenth.

0.1 seconds

0.2 seconds

0.3 seconds

0.9 seconds

Answer 1

The graph of b(t) = -16t² + 5t + 15 is a parabola opening downward. The maximum value of b(t) occurs at the vertex. The t-coordinate of the vertex is t = -5 / (2(-16)) = 5/32 = 0.15625 sec ≈ 0.2 sec.