Les exercices 2 & 3 , Svp, C'est pour mardi !❤Niveau 4eme .

Exercice 2 :

On appelle x son argent de poche mensuel.

10 = 2/7 * x
5 = 1/7 * x
5*7 = 7/7 * x
35 = 7/7 * x (soit 100% de son argent de poche mensuel)
x = 35/(7/7) = 35/(100/100) = 35/1 = 35

Elle reçoit 35 € d'argent de poche mensuel.

Exercice 3 :

1°) C = 1 - (2/3 + 1/4)
C = 1 - (8/12 + 3/12)
C = 1/1 - 11/12
C = 12/12 - 11/12
C = 1/12

D = (3 - 5/2)/(1+1/5)
D = (3/1 - 5/2)/(1/1 + 1/5)
D = (6/2 - 5/2)/(5/5 + 1/5)
D = (1/2)/(6/5)
D = (5/10)/(12/10)
D = 5/12

2°) E = 4/5*35/8
E = 32/40*175/40
E = 5600/1600
E = 7/2

3°) 1/12 +5/12 + 7/2
= 1/12 + 5/12 + 42/12
= 48/12
= 4