A refinery produces 3 grades of gasoline: Regular (85% octane), Mid-grade (90% octane), and Premium (95% octane). If 200 barrels of Regular, 100 barrels of Mid-grade, and 100 barrels of Premium are mixed, what is the average octane rating?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 88.75%.
Calculate total octane:
Regular: 200 × 85 = 17,000
Mid-grade: 100 × 90 = 9,000
Premium: 100 × 95 = 9,500
Total barrels = 200 + 100 + 100 = 400
Total octane = 17,000 + 9,000 + 9,500 = 35,500
Average octane = 35,500 ÷ 400 = 88.75