The auto repair shop of Quality Motor Company uses standards to control the labour time and labour cost in the shop

Solution - Note 1 - Given details are of standard cost for one motor tune up. But 50 tune up were completed during the week. So, standard cost details of 50 tune ups are needed.

Note 2 - Given that total labour variance = 96 U or -96 and labour rate variance = 90 F or 90.

Total labour variance = labour rate variance + labour efficiency variance

So, labour efficiency variance = 186 U or -186

Solution 1 - Labour efficiency variance = ( standard hours - actual hours ) * standard rate = -186

Labour efficiency variance = ( 150 - actual hours ) * $ 9 = -186

So, ( 150 - actual hours ) * $ 9 = -186

Solve for actual hours :-

So, Actual hours = 1536 / 9 = 170.6666 = 170.67 hours (rounded upto two decimal places)

So, actual labour hours spent on tune ups during the week ( 50 tune ups ) = 170.67 hours (rounded upto two decimal palces).

Actual hour spent on one tune up = 170.67 / 50 = 3.4134 hour

Solution 2 - Labour rate variance = ( standard rate - actual rate ) * actual hours = 90

Labour rate variance = ( 9 - actual rate ) * 170.67 = 90

So, ( 9 - actual rate ) * 170.67 = 90

solve for actual rate,

actual rate = 1446.03 / 170.67 = $ 8.47266 = $ 8.47 (rounded upto two decimal places)

So, actual hourly rate for tune ups = $ 8.47 (rounded upto two decimal places)