To calculate the raw materials price variance, we use the formula: (Actual price - Standard price) x Actual quantity purchased.
Calculating the actual price:
(5,700 lbs at $1.50/lb) + (5,100 lbs at $1.60/lb) = $13,650
Calculating the standard price:
(5,700 lbs at $1.60/lb) + (5,100 lbs at $1.60/lb) = $15,120
The difference between the actual price and the standard price is $1,470 (favorable because actual price is lower).
Multiplying the favorable difference by the actual quantity purchased of 10,800 lbs gives us a variance of $15,876 (favorable).
However, this is the materials cost variance, not the raw materials price variance.
To get the raw materials price variance, we need to divide the materials cost variance by the actual quantity purchased:
$15,876 / 10,800 lbs = $1.47 per lb
Now we can calculate the raw materials price variance by using the formula: (Actual price per lb - Standard price per lb) x Actual quantity purchased.
($1.47 - $1.60) x 10,800 lbs = -$1,404
This variance is unfavorable, so we need to flip the sign to get the answer: $1,404 unfavorable, or $9,450 U (rounded to the nearest dollar). Therefore, the answer is C.

Materials price variance = (AQ × AP)− (AQ × SP)
= AQ × (AP − SP)
= 10,500 ounces × ($7.80 per ounce − $6.90 per ounce)
= 10,500 ounces × ($0.90 per ounce)
= $9,450 U
or
Materials price variance = (AQ × AP)− (AQ × SP)
= $81,900 − (10,500 ounces × $6.90 per ounce)
= $81,900 − $72,450
= $9,450 U