The following four macro-economic factors were identified regarding a stock. As returns, the stock sensitivity to each factor and the related risk premium associated with each factor have been calculated as follows:

Gross domestic product (GDP) growth = 0.6 RP = 4%

Inflation rate = 0.8, RP = 2%

Platinum prices = -0.7, RP =5%

Standard and Poors 500 index return = 1.3 RP = 9%

The risk free rate is 3%

Calculate the expected rate of return using the Arbitrage pricing theory formula.