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In a certain city there are 30 colleges....

In a certain city there are 30 colleges. Each college has 15 peons, 6 clerks, 1 typist and 1 section officer. Express the given information as a column matrix. Using scalar multiplication, find the total number of posts of each kind in all the colleges.

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A college has 15 peons, 6 clerks, 1 typist and 1 section officer.
So, in matrix representation,
`A = [[15],[6],[1],[1]]`
Here, first row represents number of peons, second row represents number of clerks.
Third row represents number of typist and fourth row represents number of section officer.
As there are `30` colleges , so total number of posts,
`X = 30A = 30[[15],[6],[1],[1]] = [[450],[180],[30],[30]]`
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