1.
30% * x + 0% *20 = 20% * (x+20)
0,3*x = 0,2 * (x*20)
0,3x = 0,2x + 4
0,3x-0,2x = 4
0,1x = 4 | /0,1
x = 40
Więc zała masa syropu:
(x+20kg) = 40 + 20 = 60kg
2.
x*100%+1,8*0%=(x+1,8)*10%
x=(x+1,8)*0,10 /10
10x=x+1,8
9x=1,8 /9
x=0,2kg
3.
2% * 30 = 3% * (30 - x)
2 * 30 / 100 = 3 * (30 - x) / 100
2 * 30 = 3 * (30 - x)
60 = 90 - 3 * x
3 * x = 90 - 60
x = 30 / 3
x = 10 kg