To find the ratio of plain blue bugs to the total number of bugs, you first need to determine the total number of bugs.
You have:
- 10 blue bugs (plain)
- 2 spotted bugs
Total number of bugs = number of blue bugs + number of spotted bugs = 10 + 2 = 12 bugs.
Now, the ratio of plain blue bugs to the total number of bugs is:
\[ \text{Ratio} = \frac{\text{Number of plain blue bugs}}{\text{Total number of bugs}} = \frac{10}{12}. \]
This can be simplified by dividing both the numerator and the denominator by 2:
\[ \frac{10 \div 2}{12 \div 2} = \frac{5}{6}. \]
Therefore, the ratio of plain blue bugs to the total number of bugs is 5:6.