An ore block of length 30m and height 20m having an average width of 1.5m with sharp boundary walls is mined with a minimum mining width of 2m. If the tonnage factors are 3 t/m<sup>3</sup> for ore, 2 t/m<sup>3</sup> for wall rock and average grade of ore is 10%, the diluted grade of ore mined in percent is

Correct Answer: 8.18