A gardener wants to plant geraniums in hanging baskets to be hung outdoors during a hot, dry summer.
The gardener tests four different soil mixes (P, Q, R, and S) for their water retention. The results are shown in the table below.
| Type of soil mix | P | Q | R | S |
|---|---|---|---|---|
| Mass of dry soil mix / g | 300 | 300 | 600 | 600 |
| Volume of water retained / cm3\text{cm}^3cm3 | 12 | 27 | 42 | 30 |
| Total mass of soil mix after water was added / g | 312 | 327 | 642 | 630 |
Explain which soil mix would be the best for the gardener to use to keep the geraniums healthy during a hot summer.
