5. The direct labour strength of a section of an Engineering Factory is 100 workers paid at the rate of Rs 6.00 per day of 8 hours each. The normal production is 1,000 units per week of 48 hours. During a particular week, an order of 1500 units was completed in 7650 hours made up of 6,300 hours at normal wages and balance at overtime wages at double rate. The total wages came to Rs. 6300. Calculate the average labour cost per piece during the week and analyse the labour cost variance