Réponse :
bonjour
Explications étape par étape :
A= 2/5 x3/4
=2/5 x 3/2x2
=3/10
B=5/3x7/2x3/7x9/5
=5/3x9/5 x 7/2x3/7
=3 x 3/2
=9/2
C=20/9 x 18/50
C= 2x10/9 x 9x2/5x10
=4/5
D= 15/49 x 21/10
=3x5x7x3 / 7x7x2x5
=9/14
E= 3x5/3
=5
F=35% 240
E=240 x 35/100
=24x10 x35 / 10x10
840/10
=84
