If the thickness of the ice on a lake is x cm, it carries a truck of y ton, where y = 0.006x^2. How heavy of a truck can the ice be if it is 25 cm?
Also, same 0.006x^2, and what thickness should the ice have to withstand a 10 ton truck?
y = .006 * 25^2 so evaluate
10 = .006 x^2 so solve for x