what would be the step by step formula to find area of the tube$(5\%)$ Problem $11$: A length of clear plastic tubing is bent into a vertical $U,$ as shown in the figure, and two liquids that do not mix are poured into it$.$ Liquid A$,$ with density ${}_A$ continues from the left column into the right. Its height is $d_1$ in the left column and $d_2$ in the right column. Liquid B$,$ with density ${}_B,$ sits on top of liquid $A$ in the right column. Its height is $d_3$ above liquid $A.$