There is an antique clock exhibition

There is an antique clock exhibition. So many clock are piled up with distinct numbers tagged with them. The person managing it hangs different clocks numbers periodically on the main wall. At 9:20 am, he hung the clock number 200; at 11:00 am, he hung the clock number 30; at 4:00 pm, he hung the clock number 240. Which numbered clock will he hang on the wall when the time is 7:30pm ?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #66072