threetimes as children as adults attended a concert on Saturday. an adult's ticket coast $7 a child's $3. the theater collected a total of $6000. how many peolple bought tickets?

adults --- x

children --- 3x

7x + 3(3x) = 6000
16x = 6000
x = 375

so 375 adults and 1125 kids for a total of 1500 sold