0 - 29 => 30 de bile
a)
numere pare = 0, 2, 4 .. 28 => 15 numere pare
p = 100×15/30 = 100×1/2 = 100/2 = 50%
b)
numere prime = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 => 10 numere prime
p = ×10010/30 = 100×1/3 = 300/3 = 33,(3)%
c)
multiplu de 5 = 0, 5, 10, 15, 20, 25 => 6 numere multiplu de 5
p = 100×6/30 = 100×1/5 = 100/5 = 20%
d)
divizor al lui 24 = 1, 2, 3, 4, 6, 8, 12, 24 => 8 divizori a lui 24
p = 100×8/30 = 100×4/15 = 400/15 = 26,(6)%
e)
patrat perfect = 1, 4, 9, 16, 25 => 5 patrate perfecte
p = 100×5/30 = 100/6 = 16,(6%)
f)
cub perfect = 1, 8, 27 => 3 cuburi perfecte
p = 100×3/30 = 100/10 = 10%
g)
divizibil cu 5 = 5, 10, 15, 20, 25 => 5 numere divizibile cu 5
p = 100×5/30 = 100/6 = 16,(6)%
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numarul de bile = 5 + 15 = 20 bile
p(albe) = 100×5/20 = 100/4 = 25%
p(negre) = 100×15/20 = 100×3/4 = 300/4 = 75%
