2. On a Monday, all prices in Isla's shop are $10 \%$ more than normal. On Friday all prices in Isla’s shop are $10 \%$ less than normal. James bought a book on Monday for £5.50. What would be the price of another copy of this book on Friday?
A $£ 5.50$
B $£ 5.00$
C $£ 4.95$
D $£ 4.50$
E $£ 4.40$
SOLUTION
D

The book cost $£ 5.50$ on a Monday after prices have risen by $10 \%$. Therefore the price before this increase was $£ 5$. It follows that on a Friday, after prices have been cut by $10 \%$, the price of the book has fallen by 50 p to $£ 4.50$.