Problem: a train 150 m long running at 72 kmph crosses a platform in 20 sec . what is the length of the platform ?
Rationale: "e 250 e = 72 * 5 / 18 = 20 = 400 â € “ 150 = 250"
annotated_formula: subtract(multiply(20, multiply(72, const_0_2778)), 150)