Question 485273
Let all job is 1
If 30 men need 16 days for a task,then 30 men in 1 day do {{{1/16}}} part of job, 1 man in 1 day does {{{((1/16))/30=1/(16*30)=1/480}}} part of job.
In 20 days 1 man does {{{20*(1/480)=20/480=1/24}}} part of job
All job (1) in 20 days will be finished by {{{1/((1/24))=1*(24/1)=24}}} men