Answer
Total Cost $= {{\$}} 62$ 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).
$\left[\begin{array}{lll}
{2.10}&{1.15}&{1.30}\end{array}\right]\left[\begin{array}{c}{10}\\{30}\\{5}\end{array}\right]=[21+34.5+6.5]=[62]$
Total Cost $= {{\$}} 62$ million