Need help on the last one with a circle

The solution set for 5v2 – 125 = 0 is

Galen sold tickets of his church’s carnival for a total of $2,820. children’s tickets cost $3 each and adult tickets cost $5 each. the number of children’s tickets sold was 30 more than 3 times the number of adult tickets slod. how many children’s ticket and how many adult tickets did he sell?

What is the solution to the equation? k/6.4=8.7 2.3 5.568 15.1 55.68