Depends on what the question is actually saying:
If the "3 8" is 38 (thirty eight):
Let R = number of red marbles to begin with.
Let B = number of blue marbles
Given two facts:
R = (1/3)(R+B)
R+1 = 38. (This assumes it's a red marble added)
2nd equation gives R = 37
1st equation gives B = 2R = 2*37 = 74 blue
If the "3 8" is 3 over 8 (3/8 or three eighths):
If a non-red marble is added, the problem is unsolvable as 3/8 is greater than 1/3, but with more marbles and the same number of red marbles, the fraction of red marbles will be less than 1/3. Thus it is assumed that a red marble is added:
Let M be the number of marbles in the jar, and R be the number of red ones, then:
1/3 M = R -- one third are red
3/8 (M + 1) = R + 1 -- when an extra red marble is added, 3/8 of the marbles are now red marbles
Substituting R from the first equation into the second equation gives and solving gives:
3/8 (M + 1) = 1/3 M + 1
→ 9/8 (M + 1) = M + 3
→ 9(M + 1) = 8M + 24
→ 9M + 9 = 8M + 24
→ 9M = 8M + 15
→ M = 15
1/3 are red → 2/3 are blue
→ 2/3 x 15 = 10 are blue
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Another Answer:
1/3+1/24 = 3/8 It doesn't how many red marbles are added because now there are 24 but before there were 23 which is 1/3 of 69 of which 2/3 are 46 blue marbles.
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It depends what probability exactly you want to find.probability = number of successful ways / total number of waysIf the problem is:You have a bag containing 4 blue, 5 red, 1 green, 2 black marble what is the probability of picking a blue marble at random?Thensuccessful ways = 4 as there are 4 blue marblestotal ways = 12 as there are 4 [blue] marbles + 5 [red] marbles + 1 [green] marble + 2 [black] marbles = 12 marbles in total.pr(picking a blue) = 4/12 = 1/3Perhaps the problem is:You pick 2 marbles at random without replacing them, what is the probability that they are the two black marbles?Each picking of a marble is an event and the two events are independent (in the sense that whatever you pick first does not affect the probability of the second pick) so you multiply the probability of each together:pr(1st black) = 2/12 = 1/6pr(2nd black) = 1/11 (there is 1 less black marble in the bag)pr(2 blacks) = 1/6 × 1/11 = 1/66Perhaps it is:You pick 2 marbles at random replacing the marble after the first pick, what is the probability of picking the same colour each time?This time there are 4 possible colours and the probabilities of 2 marbles the same is calculated for each (similar to above) and then they are added together to find the total probability of 2 marbles of the same colour:pr(blue) = 4/12 → pr(2 blue) = 4/12 × 4/12 = 16/144pr(red) = 5/12 → pr(2 red) = 5/12 × 5/12 = 25/144pr(green) = 1/12 → pr(2 green) = 1/12 × 1/12 = 1/144pr(black) = 2/12 → pr(2 black) = 2/12 × 2/12 = 4/144→ pr(2 the same colour) = pr(2 blue) + pr(2 red) + pr(2 green) + pr(2 black)= 16/144 + 25/144 + 1/144 + 4/144 = 46/144 = 23/72And so on.
5+x is 5 added to another number.
one # to be added to another
The sum.
An addend is a number that is added to another.