standard costing and variances

Question :
The Perseus Co a medium sized company, produces a single product in its one overseas
factory. For control purposes, a standard costing system was recently introduced.
The standards set for the month of May were as follows:
Production and sales 16,000 units
Selling price (per unit) $140
Materials:
Material 007 6 kilos per unit at $12.25 per kilo
Material XL90 3 kilos per unit at $3.20 per kilo
Labour 4.5 hours per unit at $8.40 per hour
Overheads (all fixed) $86,400 per month.
(They are not absorbed into the product costs)
The actual data for the month of May is as follows:
Produced 15,400 units which were sold at $138.25 each
Materials: Used 98,560 kilos of material 007 at a total cost of $1,256,640 and used 42,350
kilos of material XL90 at a total cost of $132,979.
Labour: Paid an actual rate of $8.65 per hour to the labour force. The total amount paid
out, amounted to $612,766.
Overheads (all fixed): $96,840
Required: compute for
a. material price and usage variance for material x & y
b. labour rate and hours variance
c. sales price & sales volume variance