2:1

Here’s a quick refresher on the 2:1 ratio.

• Meaning: For every 2 parts of quantity A, there is 1 part of quantity B. A:B = 2:1.
• If you write A = 2x and B = x, where x is the common factor.
• If you know a total amount T that consists of the two parts, then:
  • A = (2/3) T
  • B = (1/3) T
• If you know A and the total, B = A/2. If you know B and the total, A = 2B.
• In percentage terms, A = 66.7% and B = 33.3% of the total.

Example: In a class with boys:girls = 2:1 and 90 students total:

• Boys = (2/3) * 90 = 60
• Girls = (1/3) * 90 = 30

If you have a specific problem or numbers you want to work through, share them and I’ll solve it step by step.