billy has requested his broker invest 400k into the list of investment vehicles listed here with their respective return rates. however he has some specific instructions that he would like to have them follow. His goal is to maximize his ROI given these requiements.

return rates

x1= 2.5% electornics

x2= 5.7% electronics

x3= 3.7% waterways

x4=7.7% green house gasses

x5= 12.8% pharmaceuticals

In formulating the equations in a linear programming problem billy has requested that at least 20% of the investments should be placed in a combo of pharmaceuticals and waterways

which is the best way to write this constraint?

A) X3 + X5 = .3 (all investments)