A box contains 4 red and 3 blue poker chips. Three chips are pulled random. What is the probability that all are red with a replacement

No. If red balls = 4, Total no. Of balls = 7

Prob of getting first red = 4/7

Second red = 4/7

Third red = 4/7

As all balls are taken out with replacement, therefore total no. Of red balls remain same

Probability of drawing all red = 4/7*4/7*4/7

=64/343