a) Al= 2* (L+l)*h=2*( 24+16)*20= 2*40*20= 1600 m²
b) Al*2=1600*2 = 3200m² (interior si exterior)
1m²=25g (vopsea)
3200m² *25= 80 000 g= 80 kg.(vopsea)
c)1kg............40 lei
80 kg............x
x= 80*40 :1=3200 lei (pret fara reducere)
3200 lei...............100%
x .............................20%
x=20*3200:100= 640lei (reducere de pret)
3200-640= 2560 (pretul final al cantitatii de 80 kg de vopsea)