Class 12 Matrices worksheet

Sample questions

Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.

Section A · multiple choice

1. 1.

   The number of possible orders of a matrix with 18 elements is:

   1. 7
   2. 5
   3. 12
   4. 6

   Answer

   (d) 6

   the orders are m × n with mn = 18: one for each divisor of 18

2. 2.

   A = [aᵢⱼ] is a 2 × 2 matrix with aᵢⱼ = 4i − 4j. Then A is:

   1. [−16, −32; −32, −64]
   2. [0, 4; −4, 0]
   3. [1, −3; 5, 1]
   4. [0, −4; 4, 0]

   Answer

   (d) [0, −4; 4, 0]

   a₁₂ = 4(1) − 4(2) = −4

3. 3.

   If A = [−4, 2; −5, 5] and B = [2, 5; 0, −2], then −3A + B is:

   1. [−10, 11; −15, 13]
   2. [14, −1; 15, −17]
   3. [−10, −13; −5, 11]
   4. [10, −11; 15, −13]

   Answer

   (b) [14, −1; 15, −17]

   multiply each entry of A by −3, then add B

Section B · short answer

1. 4.

   If A = [5, 6, 2; 5, 2, 6] and B = [3, −1, 3; 1, 5, −1], find A + B and A − B.

   Answer

   A + B = [8, 5, 5; 6, 7, 5]; A − B = [2, 7, −1; 4, −3, 7]

   add or subtract matching entries

2. 5.

   Find AB if A = [4, 3, 3; 0, 1, 1] and B = [−3, −3; −1, 4; 4, 2].

   Answer

   [−3, 6; 3, 6]

   a₁₁ = 4(−3) + 3(−1) + 3(4)

Section C · long answer

1. 6.

   Shop R sold 52 notebooks, 58 pens, 50 files; Shop Q sold 32 notebooks, 19 pens, 10 files. The prices are Rs 12 per notebook, Rs 23 per pen, Rs 20 per file. Use matrix multiplication to find each shop's sales.

   Answer

   Shop R: Rs 2,958; Shop Q: Rs 1,021

   [52, 58, 50; 32, 19, 10] × [12; 23; 20] = [2958; 1021]

Fresh sheets for your child

In the app, every Matrices sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.

Coming soon for Android and iPhone.

More Class 12 Mathematics