Answer and Explanation:
The computation is shown below:
a. The labor rate variance is 
= (standard rate - actual rate) × actual labor hours 
= ($20 - $19.50) × 64,000
= $32,000 favorable 
b. The labor efficiency variance is 
= (standard hours - actual hours) × standard rate 
= (62,500 - 64,000) × $20
= -$30,000 unfavorable 
c. the total flexible budget variance is 
= standard cost - actual cost 
= ($1,250,000 - $1,248,000)
= $2,000 favorable