Answer :
x=adults
y=childern
x+y=90
24.50x+13.75y=1560
so
mutliply the first equation by -13.75 and add to second equaiton
-13.75x-13.75y=-1237.5
24.50x+13.75y=1560 +
10.75x+0y=323
10.75x=322.5
divide both sides by 10.75
x=30
x=30
sub back
x+y=90
30+y=90
minus 30 both sides
y=60
x=30
y=60
30 adults
60 kids
y=childern
x+y=90
24.50x+13.75y=1560
so
mutliply the first equation by -13.75 and add to second equaiton
-13.75x-13.75y=-1237.5
24.50x+13.75y=1560 +
10.75x+0y=323
10.75x=322.5
divide both sides by 10.75
x=30
x=30
sub back
x+y=90
30+y=90
minus 30 both sides
y=60
x=30
y=60
30 adults
60 kids