Answer:
340 children, 210 adults.
Step-by-step explanation:
[tex]Let \ a \ - adults, \ c - children;\\c + a = 450\\0.75c + 2a = 600|\cdot 4\\3c + 8a = 2400;\\\\c + a = 450|\cdot(-3)\\3c + 8a = 2400\\-3c -3a = -1350\\5a = 1050 => a = 210, c = 450 -210 = 340.[/tex]