Answer:
2,100 people.
Step-by-step explanation:
If 2 out of 5 people were in favor of a new high school being built, we know that 3 out of 5 people are against the decision. We can simply use this as a fraction to find the amount of people against:
[tex]3500 * \frac{3}{5}= 2100[/tex]
Therefore, 2,100 people are against the decision.