Q: Martha has 11 butterflies in her collection. She has twice as many blue butterflies as yellow butterflies. The rest of her butterflies are black. If Martha has 5 black butterflies, how many blue butterflies does she have?
A: 4
Explain how we arrive at this answer:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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Explanation: Martha has 11 - 5 = 6 blue and yellow butterflies. Martha has 6 / 3 = 2 yellow butterflies. Martha has 2 * 2 = 4 blue butterflies.