Questions about probability (Condition/Binomial random variable)

Question

You have identical 30 balls; 5 black, 10 purple, 15 orange balls in a box.

 

Q1.If we take a ball, we make a mark on it and put it back to the box. We take one ball at a time. What is the probability of taking at least one orange ball, if we do the operation 5 times? (A ball can be marked several times). You have to solve this question by using Binomial random variable. 

Q2.Conditions are the same with the Q1. But in this problem we will do the operation until we get a purple ball. What is the probability the exactly 5th marked ball was purple? (Note that first 4 were not purple)

Q3 Conditions are the same with the Q1. Find the minimum number of operations we need to have the probability of a orange ball being marked to be at least 0.98?

Answer 1

You have to give more data, about numbers & colors of balls, in order to work these problems.