a) 4/10=2/5
12/8=6/4=3/2
24/38=12/19
36/44=18/22=9/11
200/400=100/200=50/100=25/50
b) 6/9=2/3
12/27=4/9
21/18=7/6
30/42=10/14
120/300=40/100
c) 15/20=3/4
30/45=10/15
50/75=10/15=2/3
100/200=20/40=4/8
