The answer for B is 2 and 1/4 is the most common figure size
Lets name adult price as X and child price as Y
then
1X+3Y=27 (1)
2X+5Y=48 (2)
From (1) we see that X=27-3Y
Lets replace X in (2) with this formula
2(27-3Y)+5Y=48 or 54-6Y+5Y=48 and 54-Y=48 and Y=54-48 so Y=6
From (1) X=27-3*6; X=27-18; X=9
Adult = 9<span>€
Child = 6</span><span>€</span>
the graph is shifter down 3 units.