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    So I really don't understand this question could someone please explain and show working out answers ect
    .

    Bill has some counters in a bag
    3 of the counters are red
    7 of the counters are blue
    And the rest of the counters are yellow


    Bill takes a counter from the bag

    The probability he takes a yellow is 2/7
    How many YELLOW counters are in the bag before Bill takes a counter
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    If:

    P(yellow) = 2/7
    Then, P(Red and Blue) = 5/7

    If P(any counter) = no of that counter/total amount of counters

    Then:

    5/7 = 10/total number of counters
    5 x number of counters = 70
    Number of counters = 14
    14-10=4 yellow counters.


    Posted from TSR Mobile
 
 
 
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