Thread: Elementary Matrices

If the sales matrices for January and March (with twice as many cars of each model sold in February as January) had been
.[1 0 0], and [2 1 0]
.[4 2 3]........[6 1 4] respectively, find the sales matrix for the first quarter of the year.

I figured that the quarter year sales would be 2*January + March = [4 .1.. 0]
.................................................. .........................................[14 5 10]

However, the answers give the answer [5 ..1 ..0]
.................................................. ...[18 7 13], why is this?

Hello, DivideBy0!

You misread that February phrase . . .

If the sales matrices for January and March (with twice as many cars
of each model sold in February as January) had been:
.[1 0 0], and [2 1 0]
.[4 2 3]........[6 1 4] respectively, find the sales matrix for the first quarter of the year.

The total is: .[Jan] + 2·[Jan] + [Mar]

Code:

   Jan      Feb       Mar
|1 0 0|   |2 0 0|   |2 1 0|
|     | + |     | + |     |
|4 2 3|   |8 4 6|   |6 1 4|