Question

Dana a cumparat 3,5 kg de mere si 2 kg de rosii, platind, in total, 24 de lei. Luca a cumparat 7n kg de mere şi 1,5 de rosii, platind, in total, 35,5 lei, Cat costa 1 kg de rosii, respectiv 1 kg de mere?

Answer 1

3,5m+2r=24 => 2r=24-3,5m =>r=(24-3,5m)/2
7m+1,5r=35,5
7m + 15/10 × (24-3,5m)/2 = 355/10 |×20
140m+15(24-3,5m)=710
140m+360-52,5m=710
87,5m=710-360
87,5m=350
m=4 lei
r=(24-3,5×4)/2=(24-14)/2
r=5 lei

Answer 2

3,5m + 2r = 24
2r=24-3,5m
r=(24-3,5m) : 2


7m+1,5r=35,5
7m + 15/10 × (24 - 3,5m) : 2
140m + 15( 24 - 3,5m ) =710
140m + 360 - 52,5=710
87,5m=350
m=4 lei

r= (24 - 3,5 × 4) : 2
r= (24 - 14) : 2
r=10 : 2
r=5 lei

deci,
roșii=5 lei
mere=4 lei


Succes! :)