Bonjour,
2ch + 5cr = 6,70
2ch = 6,70 - 5cr
6ch+ 6cr = 13,80
6ch = 3(6,70 -5cr)
=>
3(6,70 -5cr) +6cr = 13,80
20,10 - 15cr +6cr = 13,80
20,10 - -13,80 = 15cr - 6cr
6,30 = 9 cr
cr = 6,30 / 9
1 croissant = 0,70€
2ch + 5cr = 6,70
2ch + ( 5*0,70) = 6,70
2ch + 3,50 = 6,70
2ch = 6,70 - 3,50
2 ch =3,20
1 ch = 3,20/2
1ch = 1,60
1 chocolatine = 1,60€
