Answer:
12.6 percent
Explanation:
The First Step is to Calculate the Terminal Value at end of year 4.
Terminal Value (FV) = Sum of (PV x (1 + r) ^ 4 - n)
          = $600,000 x (1.15) ^ 3 + $600,000 x (1.15) ^ 2 + $600,000 x  (1.15) ^ 1 - $500,000 x (1.15) ^ 0 Â
          = $912,525 + $793,500 + $690,000 - $500,000
          = $1,896,025
The Next Step is to Calculate the MIRR using CFj Function of a Financial Calculator :
($1,200,000) Â Â Â Â Â CFj
0 Â Â Â Â Â Â Â Â Â Â CFj
0 Â Â Â Â Â Â Â Â Â Â CFj
0 Â Â Â Â Â Â Â Â Â Â CFj
$1,896,025 Â Â CFj
Now, Shift IRR/Yr we get 12.60 %
Therefore, the MIRR is 12.60 %.