2/5:2/15=2/5*15/2=2*15/(2*5)=2*3*5/(2*5)=3
3/4:3/12=3/4*12/3=3*12/(4*3)=3
4/7:4/21=4/7*21/4=4*21/(7*4)=3
13/15:13/45=13/15*45/13=13*45/(15*13)=13*15*3/(15*13)=3
2/5:6/25=2/5*25/6=2*25/(5*6)=2*5*5/(5*2*3)=5/3
3/4:7/12=3/4*12/7=3*12/(4*7)=3*3*4/(4*7)=9/7
11/12:11/18=11/12*18/11=11*18/(12*11)=11*6*3/(6*2*11)=3/2
13/15:26/27=13/15*27/26=13*27/(15*26)=13*9*3/(3*5*13*2)=9/10
2/7:8/21=2/7*21/8=2*21/(7*8)=2*3*7/(7*2*4)=3/4
5/24:15/64=5/24*64/15=5*64/(24*15)=5*8*8/(3*8*5*3)=8/9
33/81:11/45=33/81*45/11=33*45/(81*11)=(11*3*9*5)/(9*9*11)=15/9
15/38:5/19=15/38*19/5=15*19/(38*5)=3*5*19/(2*19*5)=3/2