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 ?	Choose the correct choice from the following answers:
A) 313	B) 314	C) 315	D) 316	E) 317
Solution:   He will hang clock number 315 at 7:30pm. The person has been hanging the clock number which corresponds with the angle between the hour hand and the minute hand of the clock at that time.   Answer 315
<result>C</result>
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 ?