Answer: 158 people came to see them play.
Explanation:
Let x represent the number of people that came to see them play.
A local garage band, held a rent party. They charged $3 per person for admission. This means that the total amount that they charged for x people would be 3x
The proceeds were used to pay for the rent.
If the rent is $420 and they ended up with an extra $54 after paying the rent, it means that
3x - 420 = 54
3x = 54 + 420 = 474
x = 474/3 = 158