Answer :
There is a formula for that;
Total time = (Worker 1 * Worker 2) / (Worker 1 + Worker 2)
Total time = (80 * 120) / (80 + 120)
Total time = 9,600 / 200
Total time = 48 minutes
Total time = (Worker 1 * Worker 2) / (Worker 1 + Worker 2)
Total time = (80 * 120) / (80 + 120)
Total time = 9,600 / 200
Total time = 48 minutes