Question

If you have 50 red bead 50 blue beads 50 green beads what I'd the probability that will be blue

Answer 1

Add all the beads together and put it over the number of blue beads.
so since there are 150 beads, the denominator is 150. and the amount of blue beads is 50 so that's the numerator.
50/150 now simplify, divide the numerator and denominator by 50 that equals
1/3
so the probability of getting a blue bead is 1/3

Answer 2

Because they are equal (50 red, 50 blue, 50 green) so the probability for blue ones is 1/3