Specific rotation of sugar solution is `0.01 SI` units. `200 kg-m^(-3)` of impure sugar solution

Specific rotation of sugar solution is `0.01 SI` units. `200 kg-m^(-3)` of impure sugar solution is taken in a polarimeter tube of length `0.25m` and an optical rotation of `0.4` rad is observed. The percentage of purity of sugar in the sample is

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