17.21 USE problems

Problem: In the cuboid \( A B C D A_{1} B_{1} C_{1} D_{1} \) the lengths of the edges are \( A D=12, A B=5, A A_{1}=8 \). Find the volume of the pyramid \( M B_{1} C_{1} D \), if \( M \) is a point on \( A A_{1} \) moreover \( A M=5 \).