**Solution:**

C P of 1 toffee=10/11

SP of 1 toffee=10/9

Cost price of two toffees of different kinds = 10/11+ 10/9 =200/99

Therefore, combined cost price of one toffee =1/2 x 200/99 =100/99

It is given that, selling price of 1 toffee = Rs 1

As, C. P > S.P, therefore the seller get loss = (100/99) -1 =1/99

% Loss= [(1/99)/(100/99)]x 100%=1%