Answer:
Time t = 1.39 seconds
Step-by-step explanation:
Given;
Initial velocity v = 20 ft/sec
height equation;
h = -16t^2 + 20t + 6
How long does it take for the disc to be caught 3 feet off the ground;
At this point h = 3
Substituting h = 3 into the height equation;
3 = -16t^2 + 20t + 6
-16t^2 + 20t + 6 - 3 = 0
-16t^2 + 20t + 3 = 0
Solving the quadratic equation;
t = 1.39 or t = -0.14
Since t cannot be negative;
Time t = 1.39 seconds
this equals = 3 4/40 =☆ 3 1/10☆
$530.40/4= $132.60
$132.60 x 3=$397.80
Or
$530.40 x .75= $397.80
