Réponse:
a) x+28
b) 124= x+(x+28)+42
124=2x+70
2x=124-70=54
x=54/2=27
c) Prix chocolatine : p
Prix painbaux raisins : p+0.20
d) 27(p+0.20)+55p+42p=104.60
27p+5.40+55p+42p=104.60
124p=104.60-5.40=99.20
p=99.20/124=0.80 €
pain au chocolat= 0.80 €
pain aux raisins = 0.8.+0.20=1€