TABLE 2-6
The following are the durations in minutes of a sample of long-distance phone calls made within the continental United States reported by one long-distance carrier.

-Referring to Table 2-6, if 10 calls lasted 30 minutes or more, how many calls lasted less than 5 minutes?
A) 10
B) 185
C) 295
D) 500

Question

TABLE 2-6
The following are the durations in minutes of a sample of long-distance phone calls made within the continental United States reported by one long-distance carrier.
 
-Referring to Table 2-6, if 10 calls lasted 30 minutes or more, how many calls lasted less than 5 minutes?
A) 10 
B) 185 
C) 295 
D) 500

Quizplus · Accepted Answer

The table does not provide exact values for the number of calls that lasted less than 5 minutes or 30 minutes or more. Therefore, we can only use the percentages given in the table to estimate the number of calls. If 10 calls (2% of the total calls) lasted 30 minutes or more, then we can estimate that about 98% of the calls lasted less than 30 minutes. To find the number of calls that lasted less than 5 minutes, we can subtract the estimated number of calls that lasted 30 minutes or more (10 calls) from the total number of calls (500). 
Estimated number of calls that lasted less than 30 minutes = 98% of 500 = 490
Number of calls that lasted less than 5 minutes = Total number of calls - Estimated number of calls that lasted 30 minutes or more = 500 - 10 = 490
Therefore, the best choice is B, 185.

TABLE 2-6 The Following Are the Durations in Minutes of a Sample