To find the ratio of the number of sundaes without nuts to the number of sundaes with nuts, we first note the quantities given:
- Number of sundaes with nuts = 1
- Number of sundaes without nuts = 40
The ratio is calculated as follows:
\[ \text{Ratio} = \frac{\text{Number of sundaes without nuts}}{\text{Number of sundaes with nuts}} = \frac{40}{1} \]
This simplifies to:
\[ 40:1 \]
Therefore, the ratio of the number of sundaes without nuts to the number of sundaes with nuts is:
\[ \boxed{40:1} \]