There are 6 different colored signal flags which can be hoisted onto a mast (red, white, blue, yellow, green, and black).

Question

4 of the flags are randomly selected and hoisted. What is the probability that The red flag is at the top or at the bottom?

Answer 1

There are C(6,4)=15 ways to choose 4 out of 6 flags. 5 of the 15 choices contain a red flag, so the probability of having a red flag in the 4 flags is 10/15=2/3.

The probability for the red flag to be at the top is 1/4 and to be at the bottom is 1/4, so the probability for it to be top or bottom is 1/4+1/4=1/2.

Therefore the total probability is 2/3*1/2=1/3.

 

Answer 2

Top: (1/6)

Bottom: (1/6) 

Probability: 1/6 + 1/6 = 1/3