To find the part-to-part ratio for the 6th-grade averages of 100–90 to 89–80, we compare the total number of students in each range.
From the table:
- The total number of students in the 100–90 range is 32.
- The total number of students in the 89–80 range is 65.
The part-to-part ratio of 100–90 to 89–80 is therefore:
\[ 32 : 65 \]
So, the part-to-part ratio for the 6th-grade averages of 100–90 to 89–80 written using a colon is:
\[ 32 : 65 \]