I just answered this question(s). mean is average. So you just add all the numbers up per country and divide by how many numbers there are. I hope you know how to graph otherwise look it up on kan academy and the country with the lowest number for height is the gold medalist. And the top three fastest go as gold, silver and bronze<<<<in this specific order.
Option D: Two irrational solutions
Explanation:
The equation is 
Subtracting 6x from both sides, we have,

Solving the equation using quadratic formula,

Simplifying the expression, we get,

Taking out the common terms and simplifying, we have,

Dividing by 3, we get,

Hence, the equation has two irrational solutions.
300
divide 3000 by 10 to get a tenth of 3000