Concept
Probability of any event
= number of required outcomes / total number of possible outcomes
Yellow = 7
Blue = 6
Red = 2
Green = 3
Total = 18
Probability of selecting the first ball (green) without replacement
= 3/18 = 1/6
Since the first ribbon is not replaced, the total reduces to 17.
Probability of selecting the second ball (red).
= 2/17
Therefore the probability of selecting green and then red ribbon
' and ' means multiplication
Final answer
Option C = 1/51