How many kg of pure salt must be added to 100kg of…

How many kg of pure salt must be added to 100kg of 10% solution of salt and water to increase it to a 30% solution?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #5874