Word problem for age solver

Question

Nil is 23 yrs and 1 month. Shelly is 18 yrs and 7 months. Ben is as much older than shelly is younger than Nil. How old is ben?

Answer 1

23 years 1 month MINUS 18 years 7 months =

22 years 13 month MINUS 18 years 7 months = <--- borrows

4 years 6 months

Ben is 4 years and 6 months older than Nil.

23 years and 1 month PLUS 4 years 6 months =

27 years and 7 months