In a factory there are 100 skilled, 250 semi-skilled and 150 unskilled workers. It has been observed that on an average a unit length of a particular fabric is woven by a skilled worker in 3 hours by...

Extracted text: In a factory there are 100 skilled, 250 semi-skilled and 150 unskilled workers. It has been observed that on an average a unit length of a particular fabric is woven by a skilled worker in 3 hours by a semi-skilled worker in 4 hours and by an unskilled worker in 5 hours. After a training of 2 years the semiskilled workers are expected to become skilled and the unskilled workers to become semi-skilled. How much less time will be required after 2 years of training for weaving the unit length of fabric by an average worker?