How to Solve a Sets Problem

From the survey of 300 parks; 

15 had only camping 

Therefore, in the region I of the Zenn diagram we place 15. 

35 parks had only picnicking 

Therefore; 

20 had only hiking trails 

Therefore; 

185 had camping and 140 camping and hiking trails 

Therefore; 

Hence; 

Also; 

Substituting equation 1 into 2 give; 

Therefore; 

125 had camping and picnicking 

Therefore; 

Thus, 

We can use equation 2 to calculate VI since we have V 

210 had hiking trails 

This means that; 

Therefore; 

Determining the value of VIII 

Therefore; 

Venn diagram 

Question 

Determine the number of parks that; 

Had at least one of these features 

Had all three features 

Did not have any of these features 

Had exactly two of these features