Răspuns :
1) 89 + 10% x 89 = 89 + 89 x 10 : 100 = 89 + 8,9 = 97,9 lei2) 97,9 -10% x 97,9 = 97,9 - 97,9 x 10 : 100 = 97,9 - 9,79 = 88,11 lei
89 + 10%·89
= 89 + 89·10/100
= 89 + 8.9
= 97.9 lei
--------------------------
97.9 -10%·97.9
= 97.9 - 97.9·10/100
= 97.9 - 9.79
= 88.11 lei
= 89 + 89·10/100
= 89 + 8.9
= 97.9 lei
--------------------------
97.9 -10%·97.9
= 97.9 - 97.9·10/100
= 97.9 - 9.79
= 88.11 lei