1 kg of potatoes costs x, 1 kg of carrots costs y.
8x+5y=28 | :(-4)
2x+3y=11,2
-2x-1,25y=-7
2x+3y=11,2
3y-1,25y=11,2-7
1,75y=4,2
y=2,4
1 kg of carrots costs $2,4.
1 kg of potatoes costs:
2x+3*2,4=11,2
2x+7,2=11,2
2x=11,2-7,2
2x=4
x=2
1 kg of potatoes costs $2