$2\mathrm{.}85$ Forms used to make a concrete basement wall are shown in Fig. P$2\mathrm{.}85.$ Each $4-$ft$-$long form is held together by four ties$-$two at the top and two at the bottom as indicated. Determine the tension in the upper and lower ties. Assume concrete acts as a fluid with a weight of $150l\frac{b}{f}{t}^3.$

Figure P$2\mathrm{.}85$