The great Central bridge in Japan is 7.64MI how long will it take you to cross the bridge if you were walking at 4 mi/h

Anyone know these questions? i need ,.

Ahmed plans to add a rectangular sunroom to his house. the sunroom will have a length of 14 feet and a width of 10 feet, and the construction will cost $40 per square foot. how much more would the sunroom cost if it’s width were increased to 12 feet?

Benefit(s) from large economies of scale, in which the costs of goods decrease as output increases. natural monopolles perfect competition