Answer:
after 3.92 seconds
Explanation:
Given the quadratic equation that models the sledge distance expressed as;
d = -5x^2 + 77
The sled get to the bottom of the hill at when d = 0. Substitute into the equation given;
0 = -5x^2 + 77
5x^2 = 77
x^2 = 77/5
x^2 = 15.4
x = √15.4
x = 3.92
Hence the sled get to the bottom of the hill after 3.92 seconds