Someone please help i will mark brainliest<3 thank you!:) you can zoom in:)

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?

Someone me! if you’re smart you can solve this!

Use sigma notation to represent the following series for 9 terms.