Estimate the area of the patio

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?

The function show two sisters' savings account and the rate at which they plan to deposit money

Answer! if you don’t mind, can you explain