1. (10 points). Two scientific and production enterprises supply the market with substrates for growing orchids. In the substrate "Orchid-1," pine bark is three times more than sand; peat is twice as much as sand. In the substrate "Orchid-2," bark is half as much as peat; sand is one and a half times more than peat. In what ratio should the substrates be taken so that in the new, mixed composition, bark, peat, and sand are present in equal amounts.
Solution. In the first substrate, bark, peat, and sand are in the ratio 3:2:1, in the second substrate, they are in the ratio 1:2:3. Let's take a parts of the first mixture and b parts of the second. Then $3a + b = 2a + 2b = a + 3b$. We get $a = b$.

Answer: $1: 1$.

| Points | Grading Criteria |
| :--- | :--- |
| 10 points | Justified solution |
| 5 points | An arithmetic error is made in an otherwise justified solution or the solution is insufficiently justified. |
| 0 points | All other cases |