Please help with excel formulas for this

Standard $6.60 2.4 yards @ 3 yards @ $2.75 per yard $2.70 per yard Actual $8.10 Direct labor: Standard 10.80 0.6 hours @ 0.5 hours @ $18.00 per hour $22.00 per hour Actual 11.00 Variable overhead: Standard 0.6 hours @ 4.20 $7.00 per hour $7.10 per hour Actual 0.5 hours @ 3.55 Total cost per unit $21.60 $22.65 Excess of actual cost over standard cost per unit $1.05 Using formulas, compute the amount of the unit cost difference that is traceable to each of the variances computed above. Materials: Quantity variance Price variance Labor: Efficiency variance Rate variance Variable overhead: Efficiency variance Rate variance Excess of actual over standard cost per unit