I don't think this is enough information to answer this. Suppose there are 100 marbles.

The probability of selecting a blue marble on the first pick is $\frac{1}{5}$

The probability of selecting a blue marble on the second pick is $\frac{19}{99}$

3rd pick $\frac{18}{98}$, 4th $\frac{17}{97}$

The product of these is 0.00123558.

Now suppose there are 1000 marbles.

These probabilities become $\frac{1}{5}, \frac{199}{999}, \frac{198}{998}, \frac{197}{997}$

and the product of these is 0.00156179

in the limit as $N \to \infty$ you'd expect that the probability of selecting 4 blues becomes

$\left(\frac{1}{5}\right)^4=\frac{1}{625}=0.0016$