Answer:
81000 people went to Bonnaroo.
192000 people went to Lollapalooza.
Step-by-step explanation:
Given:
Total number of people attending festivals, 
Number of people attending Lollapalooza is 30,000 more than twice the people attending Bonnaroo.
Unknown:
Number of people attending Lollapalooza and Bonnaroo.
Let the number of people attending Bonnaroo be
.
Therefore, the number of people attending Lollapalooza is equal to 
Evaluate:
Sum of people attending Bonnaroo and Lollapalooza is equal to the total number of people attending the festivals. So,

Substitute and Solve:
Now, we have,
.
Substitute 81000 for
and solve for the number of people attending both the festivals. This gives,
Number of people attending Bonnaroo = 
Number of people attending Lollapalooza = 
Therefore, 81000 people went to Bonnaroo and 192000 people went to Lollapalooza.