Elliott purchased shares of microsoft in 2008 for $28 per share. he plans to sell them as soon as the price rises 20%. at what price will he sell his shares?

Since we are to find the price when it is risen 20%, therefore the fractional increase must be 0.20 of the original, therefore:

amount increased = $28 * 0.20 = $5.60

So the selling price must be:

selling price = $28 + $5.60 = $33.60

b.an increase in a causes b to decrease