$\text{a)}8000:20=800:2=400$  

$\text{b)}4800:400=48:4=12$  

$\text{c)}10000:500=100:5=20$  

$\text{d)}26000:13000=26:13=2$  

$\text{e)}50000:2000=50:2=25$  

$\text{f)}60000:30000=6:3=2$