The sum of the lengths is 13.39 feet.
Since the string rolls up by 80% of the original length. He sets up a tape measure and throws the yoyo 3 times.
So,
= 3 + 2.4 + 1.92 + 80% of 1.92 + 80% of 1.536 + 80% of 1.2288 + 80% of 0.983 + 80% of 0.7864 + 80% of 0.6291 + 80% of 0.5033
= 3 + 2.4 + 1.92 + 1.536 + 1.2288 + 0.9830 + 0.7864 + 0.6291 + 0.5033 + 0.4026
= 13.39 feet
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