In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No Error'. The task of(A)/writing a autobiography(B)/is a difficult one.(C)/No error(D)
A boy spends Rs 20 to purchase toffees at Rs 1 each. Next day, he purchased some toffees for Rs 40 with a discount of 50 paise per toffee. What is the average price per toffee (in paise)?