EM-2134

Matrix multiplication

E Math · Secondary 4 · Hard · Matrix multiplication

In a stationery shop, a pen costs \.20 and a notebook costs \$2.50. Another shop sells the same pen for \$0.30 less and the same notebook for \$0.40 more.

The prices in the two shops are represented by the matrix

Q = \begin{bmatrix} 1.20 & 2.50 \\0.90 & 2.90 \end{bmatrix}.

A customer buys 3 pens and 4 notebooks.

Find the total amount he would pay in each shop by evaluating the matrix product

R = PQ

, where

P = \begin{bmatrix}3 & 4\end{bmatrix}.

What is matrix

R

$\begin{bmatrix}13.6 & 14.3\end{bmatrix}$
$\begin{bmatrix}14.3 & 13.6\end{bmatrix}$
$\begin{bmatrix}10.6 & 12.7\end{bmatrix}$
$\begin{bmatrix}6.1 & 5.8\end{bmatrix}$

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