lccc
posted by daniel on .
An urn contains 4 red and 3 blue marbles. What is the probability when three marbles are selected randomly that all 3 will be red, if we select each marble
a) with replacement
b) without replacement

Please type your subject in the School Subject box. Any other words, including obscure abbreviations, are likely to delay responses from a teacher who knows that subject well.

with replacement:
prob = (4/7)(4/7)(4/7)
without replacement:
prob = (4/7)(3/6)(2/5)