The Armstrong Company manufactures bicycle frames. Armstrong budgets to use 5 pounds of a carbon-composite material to produce one frame. Armstrong budgets to pay $40 per pound of the carbon-composite material.
In December of the most recent year, Armstrong manufactured 225 bicycle frames using 1,125 pounds of the carbon-composite material. To obtain a quantity discount, however, Armstrong’s purchasing manager actually acquired 1,500 pounds of the carbon-composite material during December at a total cost of $56,250.

Required:
a. What is Armstrong’s material price variance for December? What is Armstrong’s purchase price variance for December?
b. Which variance, the materials price variance or the purchase price variance, would you recommend that Armstrong use?