In a set of 30 game cards, 17 are white and rest are green. 4 white and 5 green are marked IMPORTANT. If a card is chosen randomly from this set, what is the possibility of choosing a green card or an ‘IMPORTANT’ card?

Answer: Option C

We want green card or IMPORTANT card
There are 30 - 17 = 13 green cards
There are 4 + 5 = 9 IMPORTANT cards
Total cards = 30
Also 5 green cards are IMPORTANT cards
So probability
$$\begin{array}{rl}& =\frac{13}{30}+\frac{9}{30}-\frac{5}{30}\\ & =\frac{17}{30}\end{array}$$