Half-Value Layer Tube Potential Lead HVL Concrete HVL 40…

Half-Value Layer Tube Potential Lead HVL Concrete HVL 40 kVp .03 mm 3.3mm 60 kVP .11 mm 6.4 mm  80 kVp .19 mm 11 mm 100 kVp .24 mm 15 mm 125 kVp .27 mm 20 mm Using the chart above, how much concrete would be required to reduce a 100 kVp x-ray exposure to half of its intensity?