So first divide 600/15
That comes to 40.
Next we will do 12 x 40 because only 12/15 people actually agreed with the idea.
That comes to 480.
Now do 600-480
That comes to 120.
So 120 people thought it was a bad idea to make the park. But the problem asked for a percent.
120/600 = .2 or 20%