60÷6 indicates how many minutes 1 hour is.
Climb 12 decimeter in 6 minutes, so you can climb 12 × (60÷6) decimeter in 6 minutes.
The third kind:
6÷60 means 6 minutes 1 hour.
Climb 12 decimeter in 6 minutes, so that you can climb12 decimeter in a ratio of 6÷60.