Consider the following production function: q equals 8 lk plus 5 upper l squared minus left parenthesis one third right parenthesis upper l cubed . given the following expressions for the marginal productivity of each input: mp subscript upper l baseline equals 8 upper k plus 10 upper l minus upper l squared and mp subscript upper k baseline equals 8 upper l assuming capital is plotted on the vertical axis and labor is plotted on the horizointal axis, determine the value of the marginal rate of technical substitution when k = 30 and l = 10. (round your answer up to two decimal places and include the proper sign.)