Find the principal which yields a simple interest of Rs

Find the principal which yields a simple interest of Rs. 20 and compound interest of Rs. 28 in two years, at the same percent rate per annum?

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 #10425