A storage container is shaped like a rectangular prism measuring 6 by 4 by 5, topped with a pyramid of the same base and a height of 3.…

The container is a prism with a pyramid on top. The prism has volume $6\cdot4\cdot5=120$. The pyramid has the same base, $6\cdot4=24$, and height $3$, so its volume is $\frac{1}{3}(24)(3)=24$. The total is $120+24=144$, choice J. Choice F ($120$) leaves out the pyramid. Choice G ($192$) uses $24\cdot3=72$ for the pyramid, forgetting the factor $\frac{1}{3}$. Choice H ($168$) uses $\frac{2}{3}$ for the pyramid. A pyramid holds exactly one third of the prism with the same base and height.