If you would like to know the unit rate that describes the relationship of the real house to the model doll house, you can calculate this using the following steps:
3.25 feet ... 30 yards
1 foot ... x yards = ?
3.25 x = 30 1
3.25 * x = 30
x = 30 / 3.25
x = 9.23 yards
The correct result would be 9.23 yards/foot.
