Question

Explain how 15years3months is converted into years

Answer 1

In one year 12 months 
so, 3 months is 3/12 =1/4
15years3months is 61/4 years 

Answer 2

One year =12 month 3month =3/12=1/4 year 15year 3month=15+1/4 = 61/4