ECZ 2021 · O-Level Paper 2 · Question 1 — Probability
A box contains 3 black and 2 white marbles of the same size. A marble is taken out at random from the box and not replaced. A second marble is then drawn.
(a) Simplify a - 12a^2 - 144.[2]
Verified working — step 1
a2 - 144 = …(b(i)) A box contains 3 black and 2 white marbles of the same size. A marble is taken out at random and not replaced, then a second is drawn. Calculate the probability that both marbles are white.[2]
Verified working — step 1
There are 5 marbles at the fi…(b(ii)) Calculate the probability that the two marbles are of different colours.[3]
Verified working — step 1
P(black then white) = (35)(24) = 620The 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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