Step-by-step explanation: 3.706, but since you need it rounded to the nearest tenth its 3.7. If you put both equations on a graph, they intercept. We use the x coordinate in this intersection as the answer.
When stone hits the ground, it's height will be zero, and since we're finding the time that's required for the stone to hit the ground, we can set h = 0 and solve for t.
