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Question
The following table gives the life times of 400 neon lamps:-
| Life time (in hours) | Number of lamps |
| 300 - 400 | 14 |
| 400 - 500 | 56 |
| 500 - 600 | 60 |
| 600 - 700 | 86 |
| 700 - 800 | 74 |
| 800 - 900 | 62 |
| 900 - 1000 | 48 |
- Represent the given information with the help of a histogram.
- How many lamps have a life time of more than 700 hours?
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Solution
(i) By taking the life time (in hours) of neon lamps on the x-axis and the number of lamps on the y-axis, the histogram of the given information can be drawn as follows:
Here, 1 unit on the y-axis represents 10 lamps.
(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 a lifetime of more than 700 hours is 184. (74 + 62 + 48 = 184)
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