Răspuns :
a) 5/X x 80 = 100
400/X = 100
100X = 400
X = 4
b) 10/X x 21 = 30
210/X = 30
30X = 210
X = 7
c) 17/X x 180 = 153
3060/X = 153
153X = 3060
X = 20
d) 34/X x 4800 = 13600
163200/X = 13600
13600X = 163200
X = 12
400/X = 100
100X = 400
X = 4
b) 10/X x 21 = 30
210/X = 30
30X = 210
X = 7
c) 17/X x 180 = 153
3060/X = 153
153X = 3060
X = 20
d) 34/X x 4800 = 13600
163200/X = 13600
13600X = 163200
X = 12