Over the next three weeks, Andrés developed a ritual. He would spend two hours trying to solve five problems on his own—struggling, erasing, cursing softly in Spanish. Then, and only then, would he open the solucionario.
[Q = 0.78 \times 3 \times \frac20 - (-5)0.01 = 0.78 \times 3 \times \frac250.01 = 5850 W] Over the next three weeks, Andrés developed a ritual