Hello i'm having trouble figuring out how to this problem. Please help me out by showing the answer plus how you got it so I can understand it better. Thank you so much!

The director of cost management for Portland Instrument Corporation compares each month's actual results with a monthly plan. The standard direct-labor rates for the year just ended and the standard hours allowed, given the actual output in April, are shown in the following schedule Standard Direct- Labor Rate per Hour $16.00 14.00 10.00 Standard Direct-Labor Hours Allowed, Given April Output 500 500 500 Labor class III Labor class II Labor class I A new union contract negotiated in March resulted in actual wage rates that differed from the standard rates. The actual direct-labor hours worked and the actual direct-labor rates per hour experienced for the month of April were as follows Actual Direct- Actual Direct- Labor class III Labor class II Labor class I Labor Rate per Hour $17.20 15.00 10.80 Labor Hours 550 650 375 Required 1-a. Compute the direct-labor rate variance for each labor class for the month of April 1-b. Compute the direct-labor efficiency variance for each labor class for the month of April 2. Which of the following could be considered an advantage of using a standard-costing system in which the standard direct-labor rates are not changed during the year to reflect such events as a new labor contract