IB Question-8, November-2019, HL Paper-2

Question on counting principles. Difficulty: Medium
Hope this helped :-)

[CosmicBlitz]

Thank you very much! Counting is the most difficult topic.

[abhiheheheha]

thanks so much but could you please copy paste the question into your description so it is easier to find when googling :) (I have been searching for 15 mins 😩)