L+l=P:2=450:2=225
L-40=l-10
L+l=225
L-l=30
adunand ecuatiile , obtinem
2L=255⇒L=127,5m=12,75dam
l=L-30=127,5-30 =97,5m=9,75dam
S=12,75 dam*9,75 dam=124,3125 dam²=124,3125 ari
1 ar....100kg struguri
124,3125ari......x kg struguri
marimi direct proportionale (cu cat avem o suprafata cultivata mai mare , cu atata avem mai multi struguri)
x=124,3125*100=12431,25kg=12,43125t