Ironworker

When you're 100 feet or so above the ground and balancing on an 8-inch wide steel beam, you don't want to be distracted by too much complex math.

But ironworkers do encounter math in their jobs. They may have to estimate lengths or heights or figure out how long a project will take.

You are the supervisor of the construction going on atop a 20-storey highrise. The project is nearing the end and you need to order enough bolts to complete the job.

You have two storeys left to complete. The 19th floor will take 1,200 yards of steel beam. The top floor will take 800 yards of beam.

On the 19th floor, you will need to bolt the beams every 5 inches. On the top, you will need a bolt every 4 inches.

How many bolts do you need in total?