Some changes are listed below

a) Paper $\to$  Burnt paper        

b) Cold water $\to$  Hot water

c) Raw mango $\to$  Ripen mango                                   

d) Whole chalk $\to$  Broken chalk pieces

e) Ice $\to$  Water                                                           

f) Child $\to$  Adult

The ratio of the number of physical changes to the number of chemical changes is