A survey of 500 showed the following

15 had only camping
20 had only hiking trails
35 had only picnicking
185 had camping
140 had camping and hiking trails
125 had camping and picnicking
210 had hiking trails
Determine the number of parks that had at least one of the features

Fill in the given values using Venn diagrams

To determine the number of parks that had at least one of the features (camping, hiking trails, or picnicking), we need to add up the number of parks that had each individual feature and subtract any parks that had multiple features.

Let's break it down step by step:

1. Number of parks with only camping: 15.
2. Number of parks with only hiking trails: 20.
3. Number of parks with only picnicking: 35.

Note that these numbers represent unique parks that only have one feature.

Now, let's consider the parks that have multiple features:

4. Number of parks with camping and hiking trails: 140.
5. Number of parks with camping and picnicking: 125.
6. Number of parks with hiking trails: 210.

To calculate the number of parks that had at least one of the features, we need to add the total number of parks with each individual feature (including those with multiples) and then subtract the parks that have multiple features, as we don't want to count them twice.

Total number of parks with camping: 15 + 185 = 200.
Total number of parks with hiking trails: 20 + 140 + 210 = 370.
Total number of parks with picnicking: 35 + 125 = 160.

Now, let's calculate the number of parks that had at least one of the features:

Total = (Number of parks with camping) + (Number of parks with hiking trails) + (Number of parks with picnicking) - (Number of parks with multiple features)

Total = 200 + 370 + 160 - (140 + 125)

Total = 200 + 370 + 160 - 265

Total = 465

Therefore, there were a total of 465 parks that had at least one of the features (camping, hiking trails, or picnicking).