practical application of mathematics in daily life

This is just an account but good stories, especially children's stories needs to have a morale towards the tale and Wall-e just isn't exception. The story is approximately how a humans had treated planet earth so while living there that they just exhaust space to dispose of all of the rubbish that they created. All the humans had left earth to travel continue to exist a spaceship for 5 years as the mess was settled by robots but the earth became toxic and killed everything that was living except a strange bug or two. 700 years later the humans remained living aboard the spaceship waiting for indications of life in order to return. During the year 1930 there was one engine which as on hype named as 'Ricardo' sleeve valve engine. Mirrlees the period introduced two Mirrleesengines represented this patent type of the valve engine. Well the first kind had bore of around 5.5 inches and developed a stroke of just about 6.5 inches and produced 20BHP each cylinder at rate of 900 r.p.m. the other had 17 inches bore and 21.5 inches stroke, giving 50BHP per cylinder on the rate of 200 r.p.m.