A grocer mixes two types of coffee, one costing $8 per pound and another costing $12 per pound, to create a blend. If the blend costs $10 per pound, and there are 30 pounds of the cheaper coffee in the blend, how many pounds of the more expensive coffee are in the blend?

The correct answer to the question "A grocer mixes two types of coffee, one costing $8 per pound and another costing $12 per pound, to create a blend. If the blend costs $10 per pound, and there are 30 pounds of the cheaper coffee in the blend, how many pounds of the more expensive coffee are in the blend?" is Option D: 30 pounds.

The other options — A) 15 pounds, B) 20 pounds, C) 25 pounds — are incorrect for this GMAT Exam Prep question. As explained above: Let x be the pounds of expensive coffee. Total cost equation: 8(30) + 12x = 10(30 + x). 240 + 12x = 300 + 10x. Subtracting 10x and 240 from both sides: 2x = 60. So, x = 30 pounds.