Light glows for every 20 seconds . How many max. times did it glow between 1:57:58 and 3:20:47 am.
Choices.
A) 380 times	B) 381 times	C) 382 times	D) 248 times	E) 482 times
Time difference is 1hr,22min,49sec=4969sec. So, light glows floor(4969/20)=248 times.   ANSWER:248 times
<result>D</result>
Light glows for every 20 seconds . How many max. times did it glow between 1:57:58 and 3:20:47 am.