# Hard SAT Math Question 67 — Video Explanation | 1600.now

Source: https://1600.now/hard/67

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67

There are four different colors of playing cards within a deck. Specifically, there are $21$ green cards, $7$ blue cards, and $12$ yellow and red cards. Given that a randomly selected card is not blue, the probability of selecting a yellow card is $\frac{1}{3}$. How many red cards are in the deck?