January 22, 2007

scribe post: Exam Rehearsal Probability

Hello guys!!!!!
Our topics in mathematics just ended. For us it is a relief but we must always put in mind that learning in a never ending process so there are still maths stuffs out there waiting for us. Anyway, this morning we did a rehearsal examination in probability. Mr. K gave us 30 minutes to work on it then after that we had a group discussion where we talked about our answers and did some brainstorming. Afterwards, Mr. K discussed with to us the right answers with their respective solutions. The questions given are:

(1) A certain soccer player has scored on 82% of his penalty kicks throughout his career. Given this information, the probabality that he will score on exactly 4 of his next 5 penalty kicks, correct to the nearest hundredth, is

(a) 0.80
(b) 0.66
(c) 0.41
(d) 0.08

The answer is (c) 0.41 because the solution for this problem is

(2) If P(A) = 3/4 and P(A and B)= 1/2, where A and B are dependant events, then P(BA) equals:

(a) 1/4
(b) 3/8
(c) 2/3
(d) 5/4

The answer is (c) 2/3. The problem indicated that A and B occured in dependant events, which means that both have to happen.

Solution:

P(A) * P(B) = 1/2

3/4 * P(B) = 1/2

P(B) = 1/2 * 4/3

P(B) = 2/3

(3) Peter places 5 equal-sized tiles in a cloth bag. Each tile has a letter on it. The letters are P, E, T, E and R. The probability that Peter selects the 5 tiles, one at a time, in order such that they spell PETER, correct to the nearest hundredth, is

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(4) A child 2 quarters, 2 dimes, and 3 nickels in his pocket, but he does not understand the value of any of the coins. He puts 35cents worth of candy on the counter at a store and randomly selects two coins from his pocket. The probability that the two coins he selects will have a total at least as high as the value of the candy is:

(5) It is known that 53% of graduating are boys. Three are chosen at random. Given that at least two of the three grads are boys, determine the probability that all three of the grads are boys. ( Answer accurate to at least 4 decimal places. )

Well that's all folks.....
The next scribe is JESSICA!!!!!!!!
I already told her that she is next scribe...
Anyway guys, good luck to all...
May the good news be ours after the provincial exam....
God bless us all!!!!!!!!!