materials price variance = AQ(AP-SP)
where AQ is actual quantity, AP is actual price, SP is standard price

Because the problem is asking for price variance for units used, quantities are in units used.

AP = $105,000/35,000 = $3  (we use quantity purchased here and only here because unit price is the same, we used a portion of what we purchased for the $105k)

1 unit of final product requires 2 units of raw material (standard quantity allowed), so 12k units final product requires 24k units raw material.
SQ = 24k
SP = ($60k standard allowed)/(24k units allowed) = $2.50

We still need AQ, and we are not given it.  But, we are given that there was an unfavorable quantity variance of $2500.
materials quantity variance = SP(AQ-SQ)
2500 = 2.5(AQ-24,000)
AQ - 24,000 = 1000
AQ = 25k

Now we can plug into the materials price variance formula:
materials price variance = AQ(AP-SP) = 25k($3-$2.5) = $12,500
This is unfavorable because actual price > standard price