Step 1: Assume number of apples.
Let the fruit seller buy 20 apples in the first case and 20 in the second case (equal numbers for convenience).
Step 2: Find cost price (C.P.) of first lot.
Rate = 5 apples for Rupees 6.
So, cost of 20 apples = \(\dfrac{20}{5} \times 6 = 4 \times 6 = Rupees\; 24\).
Step 3: Find cost price of second lot.
Rate = 4 apples for Rupees 5.
So, cost of 20 apples = \(\dfrac{20}{4} \times 5 = 5 \times 5 = Rupees \; 25\).
Step 4: Total cost price.
Total apples = 20 + 20 = 40.
Total C.P. = 24 + 25 = Rupees 49.
Step 5: Selling price (S.P.) of all apples.
Rate = 9 apples for Rupees 11.
So, S.P. of 40 apples = \(\dfrac{40}{9} \times 11 = \dfrac{440}{9} \approx Rupees 48.89\).
Step 6: Calculate loss.
Loss = C.P. - S.P. = \(49 - \dfrac{440}{9} = \dfrac{441 - 440}{9} = \dfrac{1}{9}\).
Step 7: Loss percentage.
\[
\text{Loss \%} = \dfrac{\text{Loss}}{\text{C.P.}} \times 100
= \dfrac{\tfrac{1}{9}}{49} \times 100
= \dfrac{100}{441} \%.
\]
\[\boxed{\text{Loss } \dfrac{100}{441} \%}\]