Question 424727
children's ticket x numbers
adult ticket 	y  numbers

...
x+y=275	.............1				
4x+7y=1175	.............2				
multiply (1)by 	-7									
Multiply (2) by 	1									
-7x-7y=-1925					
4x+7y=1175					
Add the two equations							
-3x=-750					
/-3									
x=250 children's tickets					
plug value of x	in (1)				1	x	+	1
y=275					
250+y=275					
y=275-250
y=25 adult tickets