A radiation worker from a nuclear power plant comes to you and says that he would like to reduce the


A radiation worker from a nuclear rule introduce comes to you and says that he would approve to diminish the radiation he is receiving by an affixed 75%. After doing your homework, you ferret-out that he is currently being protected by one row of guide bricks closely 10 cm confused and that these bricks are capable of reducing the moderate concentration of the radiation by 50%. How sundry affixed rows of guide bricks should be external to the pristine row of bricks to diminish the radiation by another 75%?