Light glows for every 21 seconds . How many max. times did it glow between 1:57:58 and 3:20:47 am. Select:  A) 380 times  B) 236 times  C) 382 times  D) 392 times  E) 482 times
Time difference is 1hr,22min,49sec=4969sec. So, light glows floor(4969/21)=236 times.   ANSWER:236 times
<result>B</result>
Light glows for every 21 seconds . How many max. times did it glow between 1:57:58 and 3:20:47 am.