ECZ 2019 · O-Level Paper 2 · Question 1 — Matrices
Matrix A = 6x23. A box contains 4 red pens and 5 green pens. A pen is picked at random from the box without replacement and a second pen is then picked.
(a(i)) Given that matrix A = 6x23, find the value of x for which the determinant of A is 36.[2]
Verified working — step 1
det A = (6)(3) - (x)(2) = 18 - 2x(a(ii)) Hence, find the inverse of A.[2]
Verified working — step 1
With x = -9, A = 6-923 and det A = …(b(i)) A box contains 4 red pens and 5 green pens. A pen is picked at random without replacement and a second pen is then picked. Draw a tree diagram to illustrate the outcomes.[3]
Verified working — step 1
There are 9 pens at the first pick and 8 at th…(b(ii)) What is the probability of picking one red pen and one green pen?[2]
Verified working — step 1
P(red then green) = (49)(58) = 2072The full step-by-step working and final answer are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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