maths paper4 !!!!!! discussion

[brainiac]

hey guys how do we do this probability question ??????????//

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in this paper question 5 :%) :%) :%) :%) :%) :%) :%) :%) :%) :%) :%) :%)





thanxx in advance

 

[Aahmsil]

Solution

Question 5 (a)

Part (i)

Here they haven't specified a particular colour and hence all the cards must be considered. Given that there are only 2 cards with the letter 'D' on them out of a total of 10, the answer will be:
P = 2/10 = 0.2

Part (ii)
Since there are 4 red cards out of the 10 present, the answer will be:
P = 4/10 = 0.4

Part (iii)
In probability we generally make use of two operators; 'OR' and 'AND'.
For AND we use multiplication [x] and in the case of OR, we addition [+].
Since the question here states, 'the card is red OR the letter on the card is D' we have to use addition (as the word 'or' is mentioned).
Probability of getting a red card we've found in Part (ii) to be 0.4 and probability of getting a cad with the letter 'D' we've found in Part (i) to be 0.2
Therefore, the answer will be:
P = 0.2 + 0.4 = 0.6

Part (iv)
Since the operator is AND, we use multiplication.
Therefore the answer will be:
P = 2/10 x 4/10 = 2/25 = 0.08

Part (v)
The answer for this is '0' since there are no red cards with the letter 'N' on them.

I checked the marking scheme but the answers there to parts (iii) and (iv) are different. However I can only presume that there was an error in the marking scheme since I can't deduce any mistakes in the logic I've used or my working.

If anyone does notice any mistakes please do reply and tell me where I went wrong.

Hope that helped !!!

Cheers !!! :good: