1. A large fuel tank is in the shape of a cylinder. The material for the top and bottom of the cylinder costs $20/m^2 , while the material for the lateral surface costs $15/m^2 . The volume of the cylinder must be 120m^3.

Determine the dimensions of the most economical cylinder.

Surface Area Formula used : SA = 2 x pi x r^2

Volume Formula use: V = pi x r^2 x h

2. In a swim/run race, competitors start at point A , and must swim across a river (to any point on the opposite shore), then run along the shore to the finish point at point B. The river is 1 km across, and the finish is 5 km downstream from the start. If Olivia can swim 4km/h and run 10km/h, determine the route she should take to finish the race as quickly as possible.