To find the fraction of Swarna's pocket money that she donated, we need to subtract the fractions she spent from 1 (the whole).
Step 1: Swarna gave 1/4 of her pocket money to her brother.
Remaining money = 1 - 1/4 = 3/4
Step 2: Out of the remaining money, she spent 1/3 for buying a book.
Remaining money after buying the book = 3/4 - 1/3
To subtract fractions with different denominators, we need to find a common denominator.
Step 3: Find a common denominator for 4 and 3, which is 12.
3/4 = (3/4) * (3/3) = 9/12
1/3 = (1/3) * (4/4) = 4/12
Subtract the fractions: 9/12 - 4/12 = 5/12
So, Swarna had 5/12 of her pocket money left after buying the book.
Step 4: Out of the remaining money, she spent 1/6 for watching a movie.
Remaining money after watching the movie = 5/12 - 1/6
Again, find a common denominator:
5/12 = (5/12) * (1/1) = 5/12
1/6 = (1/6) * (2/2) = 2/12
Subtract the fractions: 5/12 - 2/12 = 3/12
So, Swarna had 3/12 (which can be simplified to 1/4) of her pocket money left after watching the movie.
Step 5: Finally, Swarna donated the remaining money for charity.
The fraction of her pocket money that she donated is 1/4.
Therefore, Swarna donated 1/4 of her pocket money.