document.write( "Question 1190768: Randy can invest up to $40,000. As his financial advisor, you recommend that he place at least $10,000 in Account A yielding 2% and at most $20,000 in Account B yielding 5%. (i) Using x to denote the amount of money invested in Account A and y to denote the amount of money invested in Account B, write a system of linear inequalities that describes the possible amounts of each investments. Assume x and y are in thousands of dollars. [4]
\n" ); document.write( "(ii) Graph the system of inequalities [6]
\n" ); document.write( "(iii) Given that the objective function can be written as I=0.02x + 0.05y (where I represents income), determine how much money should be placed in each investment so that his income is
\n" ); document.write( "maximized.
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #822473 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
x = 2% investment
\n" ); document.write( "y = 5% investment\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "constraints are:
\n" ); document.write( "x >= 10
\n" ); document.write( "y <= 20
\n" ); document.write( "x + y <= 40
\n" ); document.write( "x >= 0
\n" ); document.write( "y >= 0
\n" ); document.write( "objective function is:
\n" ); document.write( "profit = .02x + .05y\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "using the desmos.com calculator, you would:
\n" ); document.write( "graph the opposite of the inequalities.
\n" ); document.write( "the area of the graph that is not shaded is you region of feasibility.
\n" ); document.write( "the corner points of the region of feasibility are where yoour maximum solution lies.
\n" ); document.write( "evaluate the objective function at each of these corner point.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "this is what the graph looks like:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "your corner points are:
\n" ); document.write( "(10,0)
\n" ); document.write( "(10,20)
\n" ); document.write( "(20,20)
\n" ); document.write( "(40,0)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "at (10,0), the profit is .02 * 10 + .05 * 0 = .2 * 1000 = 200
\n" ); document.write( "at (10,20), the profit is .02 * 10 + .05 * 20 = 1.2 * 1000 = 1200
\n" ); document.write( "at (20,20), the profit is .02 * 20 + .05 * 20 = 1.4 * 1000 = 1400
\n" ); document.write( "at (40,0), the profit is .02 * 40 + .05 * 0 = .8 * 1000 = 800\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "your maximum profit is when x = 20 and y = 20.
\n" ); document.write( "that would be 20,000 invested in account A and 20,000 invested in account B.
\n" ); document.write( ".02 * 20,000 + .05 * 20,000 = 1400.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "all your constraints need to be satisfied at that corner point.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "at (20,20):
\n" ); document.write( "x >= 10 is satisfied.
\n" ); document.write( "y <= 20 is satisfied.
\n" ); document.write( "x + y <= 40 is satisfied.
\n" ); document.write( "x >= 0 is satisfied.
\n" ); document.write( "y >= 0 is satisfied.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "let me know if you have any questions.
\n" ); document.write( "
\n" );