EM-2110

Matrix multiplication

E Math · Secondary 4 · Hard · Matrix multiplication

A shop sells pens and pencils. On Monday, 50 pens and 30 pencils are sold. On Tuesday, 40 pens and 20 pencils are sold. Pens cost \.20 each and pencils cost \$0.40 each. Represent the numbers sold in a

2\times 2

matrix

N

, and choose the matrix

C

so that the product

NC

gives the total money collected on each day.

$C = \begin{pmatrix}1.20\\0.40\end{pmatrix}$
$C = \begin{pmatrix}1.20&0.40\end{pmatrix}$
$C = \begin{pmatrix}0.40\\1.20\end{pmatrix}$
$C = \begin{pmatrix}1.20&0.40\\1.20&0.40\end{pmatrix}$

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