Question

The Des Plaines River Bridge is 2.1 km long. Engineers are considering re-lighting the bridge with a pole placed every 100 feet of the bridge length starting from the south end. Each pole will support four light globes. How many globes will be required for the re-lighting project?

Answer 1

now, there are 3280.84 feet in 1 kilometer, so, how many feet are there in 2.1km? well, 2.1 * 3280.84 or 6889.764 feet.

now, they're putting globes on intervals of 100ft, however, how many times does 100 go into 6889.764? well 6889.764/100 which is rounded up 68.9.

so, that means roughly 69 poles, however, the division excludes the starting point, so if we include that, because is lighting and thus it needs to include the starting point of the bridge, so that'd be 70 poles then.

each pole with 4 globes, 70 * 4 globes then.

Answer 2

228
hope this helped!