A stationery shop sells the items below. Find the total cost of these items:
Round your answer to two decimal places
$$(22.10, 22.1)
Hint
Help Video
Correct
Fantastic!
Incorrect
Multiplying Two Matrices
[abc]×[pqr]=ap+bq+cr
Two matrices can be multiplied only if the number of columns (n) in the first matrix is equal to the number of rows
(m) in the second matrix.
To get the total cost, form the Quantity and Cost matrices, then multiply them.
List each item’s quantity in 1 row
Pens: 6
Erasers: 2
Gluesticks: 4
Pencils: 5
Quantity Matrix:
[6245]
List each item’s cost in 1 column
Pen: $1.60
Eraser: $0.80
Gluestick: $1.35
Pencil: $1.10
Cost Matrix:
[1.600.801.351.10]
Next, proceed with multiplying the two matrices
[6245]×[1.600.801.351.10]
=
[(6⋅1.60)+(2⋅0.80)+(4⋅1.35)+(5⋅1.10)]
=
[9.60+1.60+5.40+5.50]
=
[22.10]
Therefore, the total cost of the items is $22.10
$22.10
Question 2 of 3
2. Question
Bakeries A and B buy sacks of flours, boxes of yeast and cans of baking powder from the same vendor on a weekly basis. The quantities and costs are listed below. Find the total weekly cost for each bakery in matrix format.
1.
2. AB[275244]
3. AB[240265]
4. AB[265240]
Hint
Help Video
Correct
Keep Going!
Incorrect
Multiplying Two Matrices
[abc]×[pqr]=ap+bq+cr
Two matrices can be multiplied only if the number of columns (n) in the first matrix is equal to the number of rows
(m) in the second matrix.
To get the total cost, form the Quantity and Cost matrices, then multiply them.
List each bakery’s item quantity in 2 rows
Bakery A: 15 Flour, 2 Yeast, 6 Baking Powder
Bakery B: 17 Flour, 3 Yeast, 4 Baking Powder
Quantity Matrix:
AB[15261734]
List each item’s cost in 1 column
Flour: $12
Yeast: $17
Baking Powder: $5
Cost Matrix:
[12175]
Next, proceed with multiplying the two matrices
AB[15261734]×[12175]
=
AB[(15⋅12)+(2⋅17)+(6⋅5)(17⋅12)+(3⋅17)+(4⋅5)]
=
AB[180+34+30204+51+20]
=
AB[244275]
Therefore, the total cost of the items for Bakery A is $244 and for Bakery B, it is $275
AB[244275]
Question 3 of 3
3. Question
Three tennis players A, B and C submitted an equipment list. Their lists and the cost of each item is below. Find the total equipment cost for each tennis player in matrix format.
1. ABC[1827.5019981933.50]
2. ABC[19901825.501933.50]
3. ABC[19981827.501933.50]
4. ABC[1998.5018201931.50]
Hint
Help Video
Correct
Nice Job!
Incorrect
Multiplying Two Matrices
[abc]×[pqr]=ap+bq+cr
Two matrices can be multiplied only if the number of columns (n) in the first matrix is equal to the number of rows
(m) in the second matrix.
To get the total cost, form the Quantity and Cost matrices, then multiply them.