A rainstorm increased the amount of water stored in State J reservoirs…

A rainstorm increased the amount of water stored in State J reservoirs from 124 billion gallons to 140 billion gallons. If the storm increased the amount of water in the reservoirs to 80 percent of total capacity, approximately how many billion gallons of water were the reservoirs short of total capacity prior to the storm?

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 #7161