2:1

Do you mean the ratio 2:1? If so, here’s a quick refresher you can use on exams. What 2:1 means - A:B = 2:1 means A = 2k and B = 1k for some common factor k. - Total parts = 2 + 1 = 3 parts. - Fractions: A = 2/3 of the total, B = 1/3 of the total. - Percentages: A ≈ 66.67%, B ≈ 33.33%. Common problems - If total quantity T is given: - A = (2/3)T, B = (1/3)T - If A:B = 2:1 and A is known: - A = 2B, so B = A/2 - If A:B = 2:1 and A + B = T: - 3 parts total, A = (2/3)T, B = (1/3)T - If you’re given raw amounts and want the ratio: - Example: A = 40, B = 20 → ratio simplifies to 2:1 - If you’re given a different pair but need to scale: - To scale by factor k: A = 2k, B = k Practice 1) If A:B = 2:1 and A + B = 90, what are A and B? - A = 2/3 of 90 = 60, B = 30. 2) A = 28 and A:B = 2:1. What is B? - B = A/2 = 14. 3) Find the percentage of the mixture that is B if A:B = 2:1. - B = 1 part out of 3 parts = 1/3 ≈ 33.33%. If you have a specific problem or context (chemistry mixtures, finance, algebra, etc.), paste it and I’ll tailor the solution.