1.2.5 During the summer, all bedrooms are regularly fully booked. During the winter time, it decreases by around \( 50 \% \). Write down the relationship between the summer and winter bedroom reservation as a ratio in its simplest form.

Let the number of summer reservations be \( S \). According to the problem, during winter there is a decrease of around \(50\%\), so the number of winter reservations is \[ W = S - \frac{50}{100} \cdot S = S - 0.5S = 0.5S. \] This establishes the relationship between summer and winter reservations as \[ S : W = S : 0.5S. \] Dividing both parts of the ratio by \( S \) gives \[ 1 : 0.5. \] To express this in its simplest form with whole numbers, multiply both parts by \( 2 \): \[ 1 \times 2 : 0.5 \times 2 = 2 : 1. \] Thus, the ratio of summer to winter bedroom reservations in its simplest form is \[ 2 : 1. \]