Answer:
5/12 = 0.41666666666 = 0.42 = approx 42% (I don't know how your teacher wants you to answer, fraction/decimal/percentage)
Explanation:
There are 14 + 10 = 24 total marbles.
10 are white.
P(white) = 10/24 = 5/12 = 0.41666666666 = 0.42 = approx 42%
so 10/24 = 5/12 are white