Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
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?

### Response:
Martha has 11-5= <<11-5=6>>6 blue and yellow butterflies.
Martha has 6/3= <<6/3=2>>2 yellow butterflies.
Martha has 2*2= <<2*2=4>>4 blue butterflies.
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