Answer
Total Cost $= {{\$}} 32.5$ million
Work Step by Step
Total Cost $=$ Price $\times$ Quantity
Arrange the three prices as a 1$\times$3 row matrix and
the three quantities as a 3$\times$1 column matrix.
These matrices can be multiplied (the resulting matrix is a 1$\times$1 matrix).
$\left[\begin{array}{lll}
{1.15}&{0.80}&{0.50}\end{array}\right]\left[\begin{array}{c}{10}\\{20}\\{10}\end{array}\right]=[11.5+16+5]=[32.5]$
Total Cost $= {{\$}} 32.5$ million
