Răspuns :
5z............90zile
30z............x sunt invers proportionale
x=5*90/30
x=5*3=15 zile
30z............x sunt invers proportionale
x=5*90/30
x=5*3=15 zile
5 ZIDARI...............................90 ZILE
30 ZIDARI.................................X
X=5*90/30
X=15