ECZ 2021 · GCE Paper 2 · Question 2 — Probability
A boy has a bag containing 5 green balls, 1 red ball and 4 blue balls. A ball is selected at random from the bag and not replaced. A second ball is then selected.
(a) Solve the equation 3x + 5x= 12, giving your answers correct to 2 decimal places.[5]
Verified working — step 1
3x + 5x= 12(b(i)) Draw a tree diagram to show all the possible outcomes.[2]
Verified working — step 1
Bag: 5 Green, 1 Red, 4 Blue out of 10 balls total.(b(ii)) Find the probability that the two balls are of the same colour.[3]
Verified working — step 1
Same colour outcomes: GG, RR, BB (RR impossible since only 1 red ball).The 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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