Question

A lawyer, an architect, a dentist and a doctor live in a four-storey apartment block. Their names are Armstrong, Blundell, Chan and Davis but not necessarily in that order. Armstrong lives two floors below Chan. Blundell lives on the top floor. The lawyer lives on the third floor. The architect lives immediately above the dentist. Who lives on the second floor and what is his occupation?

Answer 1

If Blundell doctor lives on the top floor, Chan the lawyer lives on the third floor, and Armstrong the dentist lives on the first floor.. then Davis the architect lives on the second floor

Answer 2

I got chan the archetect?

Answer 3

If Armstrong lives two floors below Chan and Blundell is on the fourth floor, then that means that Chan is on the third floor and Armstrong is on the first floor. Davis is the only option for being one the second floor

Answer 4

3. The matrices show the enrollment of boys and girls on the basketball, lacrosse, and soccer teams in two towns.

Town A Town B
Boys Girls Boys Girls
Basketball[84 76] Basketball [94 70]
Lacrosse [72 88] Lacrosse [88 89]
Soccer [96 100] Soccer [100 110]

A. If we let matrix A be the matrix for Town A, what is the element a21, and what does it represent?
B. If we let matrix B be the matrix for Town B, what is the address of the element that represents the number of girls enrolled in soccer in Town B?
C. What is the matrix that results when you subtract matrix A from matrix B?
D. Name the matrix you found in Part C matrix C. What is element c12, and what information does it tell you about the number of girls enrolled in basketball in Town B compared with Town A?
E. What is the matrix that shows the enrollment in Town A after a 25% increase in enrollment in all sports and in both genders? (Hint: Find 1.25A.) @Abhilash11

Answer 5

Right so in a matrix every element has an address of its own which is given by its row no. and column no. against an alphabet.

Answer 6

Its cause to get a practical way of expressing things. Now say you have 60 rows and 45 columns, so you cant possibly tell me how to locate a particular element (number) in the matrix

Answer 7

Ooh, right! @Abhilash11

Answer 8

So, first pick a corner. By convention it is the left hand top corner. That's our 0.

Answer 9

Now from there if you go towards the right, you go through the columns whereas if you go below you go via rows.

Answer 10

Now the first question - locate a21.

Answer 11

What is a21? @Abhilash11

Answer 12

The first no. (2) is the row and the second is the column (1)

Answer 13

I mean what does a21 mean?

Answer 14

Now from the left top corner, go two places below ie two rows below and 1 place towards the right ie 1st column

Answer 15

Alright

Answer 16

once youve got there, from the 2nd row imagine a horizontal line. and from the 1st column, imagine a vertical line.

Answer 17

These two intersect right? The point of their intersection gives the "address" of the element, which is....??

Answer 18

100??

Answer 19

Aah nope nope.

Answer 20

What did I do wrong

Answer 21

Its fine fine, dont worry. Ill explain it better.

Answer 22

Okay remember - columns are VERTICAL
Rows are HORIZONTAL

Answer 23

Okay? so tell me what does the 2nd row represent?

Answer 24

a horizontal line

Answer 25

Yes!

Answer 26

goood!!

Answer 27

Rows are:
84 76
72 88
96 100

Answer 28

See niccco these are rows ^
Horizontal lines

Answer 29

Yes, that!

Answer 30

And these are columns.

Answer 31

Yes :)

Answer 32

Mind it niccco that the space is not a column in matrices. rather the lines are treated as 'columns'

Answer 33

so how many columns do you see above?

Answer 34

Yes, so from the top corner I went to rows below and one place right and saw 100

Answer 35

3 columns

Answer 36

You sure you considered only the numbers?

Answer 37

or you also counted boys girls and soccer lacrosse basketball in too?

Answer 38

I just counted the numbers in Town A
84 76
72 88
96 100
I'm sorry, I started from 84 and counted down two. maybe it's 88 instead of 100?

Answer 39

Hmm now i get your problem. See you went down correct. But, you forgot, that 84 is also a no. in the matrix. So, it also has an adresss? if you start from 84, what would be its address then? 0? Im afraid there's no such thing in matrices though :-D

Answer 40

See, all you gotta do is, count 84 in column 1

Answer 41

76 will be column 2

Answer 42

0 is just the extreme left top corner. It refers to no element

Answer 43

@anonymouspow I'm sorry. I accidentally posted my question underneath yours. But I hope I answered your question correctly

Answer 44

Alright! So how exactly do i determine what the element a21 is then? I just don't understand where 21 comes from @Abhilash11