Final answer:
The probability of choosing, without replacement, another white marble is 1/5.
Step-by-step explanation:
To find the probability of choosing, without replacement, another white marble after the first marble chosen was a white marble, we need to calculate the probability of drawing a white marble from the remaining marbles in the box.
Initially, there are 5 white marbles out of a total of 21 marbles (16 green + 5 white). After drawing the first white marble, there are 4 white marbles left out of 20 marbles (15 green + 4 white). Therefore, the probability of choosing, without replacement, another white marble is 4/20 or 1/5.