The given data points are sorted as follows:
\[
\text{Sorted data} = [3, 3.2, 6.2, 12.3, 17.9, 18.2, 18.3, 27, 28.1, 29.2]
\]
Step 2: Calculate the Rank
To find the 60th percentile, we use the formula for the rank:
\[
\text{Rank} = Q \times (N + 1) = 0.6 \times (10 + 1) = 6.6
\]
where \( Q \) is the desired quantile (0.6 for the 60th percentile) and \( N \) is the number of data points (10).
Step 3: Identify the Lower and Upper Values
The rank of 6.6 indicates that we need to average the values at positions 6 and 7 in the sorted data:
\( X_{\text{lower}} = 18.2 \) (6th position)
\( X_{\text{upper}} = 18.3 \) (7th position)
Step 4: Calculate the 60th Percentile
Using the averaging formula:
\[
Q = \frac{X_{\text{lower}} + X_{\text{upper}}}{2} = \frac{18.2 + 18.3}{2} = 18.25
\]
Final Answer
The 60th percentile of the data is:
\[
\boxed{18.25}
\]