Question

Define 1 : 1 ratio.

Answer

100% (3 rated)

A 1:1 ratio means the two quantities are equal — one part for the first quantity for every one part of the second.

Explanation

  • In ratio notation, $1:1$ means the first quantity divided by the second equals 1: $1:1=\frac{1}{1}=1$.
  • It indicates equal proportions: for every 1 unit of A there is 1 unit of B. If you combine them, each makes half of the total: $\frac{1}{1+1}=\frac{1}{2}=50\%$ of the whole.
  • Units must match (e.g., 1 kg : 1 kg or 1 apple : 1 apple). If units differ, convert them to the same unit before comparing.

Examples

  • If a recipe calls for oil and vinegar in a 1:1 ratio and you use 100 mL of oil, you use 100 mL of vinegar.
  • If two teams are formed in a 1:1 ratio and there are 20 people total, each team has $20\times\frac{1}{2}=10$ people.
  • In math/set language, “1:1” is related to a one-to-one correspondence (a bijection) meaning each element of one set pairs with exactly one element of the other and vice versa.

Note: Order still indicates which quantity is first and which is second, but numerically 1:1 is symmetric because the values are equal.