SPM 2019 Add Maths Paper 2, Question 8Probability Distribution

Solved on video in English and Bahasa Melayu · 10 marks · Form 5, Probability Distribution · 6:30 video

The question

Diagram 4 shows a dart's target board at a dart game booth in a funfair, with a bullseye at the centre. The booth offers 3 darts per game. The customers have to pay RM5 to play a game. A toy bear will be given to customers who are able to hit the bullseye for the three darts' throws in a game. Bob is a dart player. By average, he hits the bullseye 7 times out of 10 darts thrown. (a) Bob would play the game if he had at least 90% chance to win at least one toy bear by spending RM30. By mathematical calculation, suggest to Bob whether he should play the game or otherwise. (b) What is the minimum number of games that Bob needed so that he can get 4 toy bears?

[10 marks]

SPM 2019 Add Maths Paper 2, Question 8: the question as drawn in Eduly's video6:30

Step 1

Let X = number of bullseyes out of 3 darts in one game. X ~ B(3, 0.7).

7 more steps, each with the reason for it, in the full solution

Final answer

(a) P(at least 1 bear) = 0.9196 > 0.9, so Bob should play. (b) 12 games

Where students lose marks

Watch out: use nCr, not nPr, in the binomial formula. In (b), round 11.66 UP to 12 because it's a minimum, not down to 11.

Watch every step of this question solved on video (6:30), with the reason behind each step and a box that checks your own answer.

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