Answer:
50%
Explanation:
You have 8 marbles in total. 4 white + 4 black. So four out of the eight marbles are white. This makes the fraction 4/8. 4/8 simplifies to 2/4 which simplifies 1/2. 1/2 is equal to 50%. So the probability of picking a white marble if there is 4 white marbles and 4 black marbles is 50%.