Mr. Alaisdair purchased 500 shares of the Royal Dutsch Shell company at $32 per share. He bought the stock at 75 percent margin. One month later, Alasdair had to pay interest on the amount borrowed at a rate of 2 percent per month. A that time, Alasdair received a dividend of $0.50 per share. Immediately after that, he sold the shares at $28 per share. He paid a comission of $10 on the purchase and $10 on the sale of the stock. Asceratin the rate of return on this investments for the one-month period ?