Question

If 6 workers complete a certain task in 12 days, how many workers are needed to finish the same task in 18 days?

Answer 1

The task requires `6 " workers" xx 12 " days" = 72 " worker-days"`

Spread over `18 " days"`, this task would require
`color(white)("XXX")(cancel(72)^4 " worker"cancel("-days"))/(cancel(18)cancel("days")) = 4 " workers"`