A contractor estimates that 3 persons could rewire Jasminder’s house in 4 days. If,he uses 4 persons instead of three, how long should they take to complete the job?

If the number of persons be more, it will take less time to complete the job

Therefore,

The number of persons and time required to complete the work are inversely proportional to each other.

Hence,

3 × 4 = 4 × x { let x be the number of days required to complete the work by 4 persons}

→x = 3 days