a.p a . P (at . P 20. (a) Prove that a + 100 100 100 [1 - (TOO) "]. (b) An item initially costs $2 000 and then its price is increased by 5%. Afterwards the price is lowered by 5%. What is the final price? (c) An item initially costs a dollars and then its price is increased by p%. Afterwards the (new) price is lowered by p%. What is the final price of the item? (After considering this exercise, look at the expression in part (a).) (d) What is the result if one first lowers a price by p% and then increases it by p%