What number could replace x to make a true statement?

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?

Can someone answer this question for me

Consider the sequence below. 3 , 1 , 1/3 , 1/9 , select the explicit function which defines the sequence.