Answer:
252 children and 395 adults
Step-by-step explanation:
Make a linear system of equations, where x represents the number of children and y represents the number of adults
x+y=648
1.50x+2.25y=1269
solve using substitution, so y=648-x,
then substitute this into the second equation, so you get 1.50x+2.25(648-x)=1269,
solve for x and you will get x equals the 252
then substitute this into the first equation, so you get 252+y=648
solve and you will get y=395