Lock Co makes a single product - a lock - and uses marginal costing. The standard cost card for one unit is as follows: A junior member of the accounts team produced the following variance statement for the month of May: Lock Co used 3,648kg of materials in the period and the labour force worked - and was paid for 1,824 hours. Required: (a) Prepare a revised report for the month of September, 2020 , in the above format, using a flexed budget. (b) Explain four general causes of variances. (15 marks) Lock Co makes a single product - a lock - and uses marginal costing The standard cost card for one unit is as follows A junior member of the accounts team produced the following variance staterment for: the month of May: Lock Co used 3,648kg of materials in the period and the labour force worknd - and was paid for 1.824 hours. Required: (a) Prepare a revised report for the month of September, 2020 , in the above format, using a flexed budget. (b) Explain four general causes of variances. (15 marks)