A shop increases the price of an item, P pounds, by a%, then decreases the new, increased price by the same percentage, a%.
(a) Show that the final price after both changes is P(1 - a2/10000) pounds.
(b) A shop increases the price of a games console, originally 250 pounds, by 10%, then decreases the new price by 10% in a January sale. Use the result from part (a), or otherwise, to work out the final price and the overall percentage change from the original price.
Show all working.
(a)(a) Show that the final price after both changes is P(1 - a2/10000) pounds.(3)
(b)(b) The original price is 250 pounds and a = 10. Work out the final price and the overall percentage change from the original price.(3)
(Total for Question 7 is 6 marks)