a light was seen at intervals of 13 seconds it for..., Simplification, General Mathematics

Question:A light was seen at intervals of `13` seconds .It was seen for the first time at `1` hrs min `50` secs.a.m. and the last time at `3 hrs``17 hrs` min `49` secs .a.m. How many times was light seen ?

A `378` 
B `375` 
C `360` 
D `384`

/94

+ AnswerD

+ ExplanationHrs      min          sec

      `3  −     17   −      4`
  `(-)1   −    54   −      50`
_____________________
      `1  −      22    −      59`
_____________________
:. Toatal time `= (1 xx 60 + 22) min. + 59 sec.`
                    `= (82 xx 60 + 59) sec. = 4979`.

Number of times the light is seen 

`= (4979/13 + 1)`

`= 384`.

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