If your car gets 31 miles per gallon, how much does it cost to drive 340 miles when gasoline costs $2.70 per gallon?

How to do this , and can some one explain

Consider a cube that has sides of length l. now consider putting the largest sphere you can inside this cube without any point on the sphere lying outside of the cube. the volume ratio -volume of the sphere/ volume of the cube is 1. 5.2 × 10−1 2. 3.8 × 10−1 3. 1.9 4. 2.5 × 10−1 5. 3.8

What’s the answer ? use the picture to see the problem