Bonsoir,
98,25 * 9+ 98,75 * 17 + 99,25 * 31 + 99,75 * 26 + 100,25 * 13 + 100,75 * 4
= 884,25+ 1678, 75 + 3076, 75 + 2593,5 + 1303,25 +403
= 9 939, 5
effectif:
9+17+31+26+13+4
= 100
9 939, 5/ 100 =99,39
