hello sir..please little explain for me 1.New product for first batch 20hrs.Learning rate 90%. If learning effect ceases after 72 batches .How long will it take to make a grand total of 100 batches? 2.New product for first unit 600hrs.Learning curve 80%.Direct labour cost is $20 per hr and variable O/H are $4per hr.During the month 5units produced.Time required to make 1859 hrs. What was the direct labour efficiency variance for this product? I had confused some area .So … explain & help me again sir Hoping …