Handling Data 3
4 marks · NormalA bag contains 6 blue, 3 red, and 1 green bead. One bead is picked at random from the bag.
Write down the probability that the bead picked is blue.
Write down the probability that the bead is not red.
What is the probability that the bead is either red or green?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) 6/10 or 0.6
(b) 7/10 or 0.7
(c) (3+1)/10 = 4/10 or 0.4
Also accept: Answers as simplified fractions or decimals
Common mistakes: Not using total number of beads
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correct probability of picking a blue bead, as a fraction or decimal.
B2 (b) · 1 mark · Correct probability of not picking a red bead.
M1 (c) · 1 mark · Method shown or implied for adding probabilities of exclusive events.
A1 (c) · 1 mark · Correct probability for red or green bead (4/10 or 0.4).
Worked solution
Total beads = 6 + 3 + 1 = 10
a) Blue: 6/10 = 0.6
b) Not red: (6+1)/10 = 7/10 = 0.7
c) Red or green: (3+1)/10 = 4/10 = 0.4