To find the ratios, both quantities should be in same unit.
$$30$$ days to $$36$$ hours
$$\Rightarrow$$ $$30\times 24$$ hours to $$36$$ hours ($$\because$$ $$1day=24hours$$)
$$\Rightarrow$$ $$720$$ hours to $$26$$ hours.
Thus the ratio is $$=\cfrac{720}{36}=\cfrac{20}{1}=20:1$$