Question

ratio of each 4 month to 1 year 6 month

Answer 1

1 yr 6 month = 18 month
so,
ratio will be
4 : 18
2 : 9

Answer 2

Here,

1 year 6 month = 1 year + 6 month
= 12 month + 6 month
= 18 month

Therefore,

4 month : 1 year 6 month = 4 month : 18 month
= 4/18
= 2/9
= 2:9