O-LevelMathematicsProbability4024/11 · May/June 2017 · Q93 Marks
A bag contains red and blue pegs. There are 40 pegs in the bag. The probability of choosing a red peg from the bag is 0.4 .
- (a)Work out the number of red pegs in the bag.[1]
- (b)More red pegs are added to the bag. Work out the number of red pegs that must be added to the bag so that the probability of choosing a blue peg is 0.2 .[2]
Mark scheme
Marking points from the official mark scheme (May/June 2017). The mark or mark type is shown in brackets.
- [1] 16
- [2] 80 B1 for 120 or 96 seen or M1 for 24/(40+x) = 1/5 or (16+x)/(40+x) = 4/5 oe
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