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The following table gives the life times of 400 neon lamps:
Length (in hours)Number of Lamps
300 - 40014
400 - 50056
500 - 60060
600 - 70086
700 - 80074
800 - 90062
900 - 100048
i) Represent the given information with the help of a histogram.
ii) How many lamps have a life-time of more than 700 hours?


Answer :

i) By taking life time (in hours) of neon lamps on x-axis and the number of lamps on y-axis, the histogram of the given information can be drawn as follows.

Here, 1 unit on y-axis represents 10 lamps.
image

ii) It can be concluded that, the number of neon lamps having their lifetime more than 700 is the sum of the number of neon lamps having their lifetime as 700 — 800, 800 - 900, and 900 - 1000.

Therefore, the number of neon lamps having their lifetime more than 700 hours is 184. (74 + 62 + 48 = 184)

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