twelve machines , each working at the same constant rate , together can complete a certain job in 6 days . how many additional machines , each working at the same constant rate , will be needed to complete the job in 3 days ?
"rate of one machine = 1 job / ( 12 * 6 ) days let x = number of machines needed to complete the job in 3 days 1 / ( 12 * 6 ) * 3 * x = 1 job x = 24 24 - 12 = 12 answer : b"
subtract(multiply(6, inverse(divide(3, 6))), 6)