To review, depending on how you organize it, a quadratic equation can be written in three different forms: standard, intercept and vertex. No matter the form, a positive a value indicates a concave-up parabola, while a negative a value means concave down.
If in 12 hours 20 inches falls in 24 hours 40 inches will fall and another 12 hours would be 60 inches. And another 12 hours you will get 2 days so your answer is 80
