Répondre :
X=(1-1/3-3/5):2
=(15/15-5/15-9/15)x1/2
=1/15x1/2
=1/30
Y=(1-1/3-3/5x2/3)x1/2
=(15/15-5/15-6/15)x1/2
=4/15x1/2
=4/30
=2/15
=(15/15-5/15-9/15)x1/2
=1/15x1/2
=1/30
Y=(1-1/3-3/5x2/3)x1/2
=(15/15-5/15-6/15)x1/2
=4/15x1/2
=4/30
=2/15