Odpowiedź :
a) 20%=400/x
20%=400/x
x≠0
20/100=400/x
1/5=400/x
x=200
b) 40%=400/x
40%=400/x
x≠0
40/100=400/x
2/5=400/x
2x=2000
x=1000
c) 12,50%=x/3200
12,5/100=x/3200
0,125=x/3200
400=x
x=400
20%=400/x
x≠0
20/100=400/x
1/5=400/x
x=200
b) 40%=400/x
40%=400/x
x≠0
40/100=400/x
2/5=400/x
2x=2000
x=1000
c) 12,50%=x/3200
12,5/100=x/3200
0,125=x/3200
400=x
x=400