A box contains 3 times as many black marbles as green marbles, all the same size?

Question

If a marble is drawn at random, find the probability that it is black or green

Answer 1

if you mean "black or green" literally, then 100%. you're guaranteed to get either a black.. or a green. If you want to know the probability of drawing a given color.. well

n marbles are green
3n marbles are black
total = n+3n
3n/4n 3/4 chance to get a black
1n/4n 1/4 chance to get a green

Answer 2

The probability of getting a black or green marble from a bag consisiting of black and green marble only = 1 , Because that event will always happen.

Answer 3

75% of the time it will be black (that's 3/4)
25% of the time it will be green (that's 1/4)

reason is that for every 4 marbles, 3 of them are black and 1 is green

Answer 4

let, black marbles = P(B) and green marbles = P(G)
given, P(B) = P(G) = 3
so, P(B) + P(G) = 6
so, P(B) = P(G) = 1/2
therefore the probability of P(B) OR P(G) = P(B) X P(G') + P(G) X P(B')
therefore, P(B U G) = (1/2 X 1/2) + (1/2 X 1/2) = 1/8

Answer 5

P(green) = 1/4 = 0.25
P(black) = 3/4 = 0.75

P(black or green) = P(green) + P(black) = 0.25 + 0.75 = 1.00

If there are only black and green marbles, you will definitely draw either a black or green.

Answer 6

let takes no. of green marbles is 1 then,
black marbles is 3*1=3
it should be black
" " " one black & one white
green

Answer 7

black m=b
green m=g
b=3*g
the box contain (b+g) =4g
the probability of green is g/4g=1/4=25%
and for black =75%

Answer 8

let x be the no of green marbles
therefore no of black marbles=3x
p(green)=x/4x=1/4
p(black)=3x/4x=3/4

Answer 9

It is BLACK?