Hilda's age is 13 7/12 years
Here, we want to calculate Jane's age, given Hilda's age and the difference between their ages.
From the question, we are told that Jane is 2 1/4 years younger than Hilda. What this means is that if we subtract 2 1/4 from Hilda's age, we will get Jane's age.
Mathematically, we proceed as follows to get Jane's age;