North West South Contribution margin $299,600 $499,700 $401,000 Controllable margin $141,000 $360,000 $210,000 Average operating assets $940,000 $1,500,000 $1,400,000 Minimum rate of return 11 % 14 % 8 % (a) Compute the return on investment for each division. North Division West Division South Division % % /3 North West South Contribution margin $299,600 $499,700 $401,000 Controllable margin $141,000 $360,000 $210,000 Average operating assets $940,000 $1,500,000 $1,400,000 Minimum rate of return 11 % 14 % 8 % (a) Compute the return on investment for each division. North Division West Division South Division % % /3