bonsoir
1 . en 2001 il vend 1/4 , restent les 3/4
2002 = 3/4 x 4/5 = 12/20 = 4/5
2. 1/4 + 4/5 = 5/20 + 12/20 = 17/20
invendu = 3/20
3. 3/20 = 6 ha
20/20 = 120 /3 = 40 ha
premier + second = 1/3 + 1/4 = 4/12 + 3/12 = 7/12
troisième = 5/12 x 2/5 = 10/60 = 1 /6
calcul B
( 1 - 4/12 - 3/12 ) x 2/5
= (12/12 - 7 /12 ) x 2/5
= 5/12 x 2/5 = 10/60 = 1/6
