Final answer:
Carlos spent 41 minutes on calls within Canada, 30 minutes on calls to the U.S., and 81 minutes on calls to Mexico, when rounded to the nearest minute as fractions of minutes are not permissible.
Step-by-step explanation:
Given the conditions that c, u, and m represent the number of minutes Carlos called within Canada, to the United States, and to Mexico respectively, we need to calculate the total number of minutes for each location using the following information:
- c = 28 minutes within Canada
- u = 30 minutes to the U.S.
- m = 84 minutes to Mexico
- 2c = m (This means that the minutes to Mexico are twice the minutes within Canada)
- c + m = 122 minutes (Total minutes within Canada and Mexico combined)
Using the two equations from c) and d), we can solve for c and m:
- 2c = m (c = m/2)
- c + m = 122
Replace c with m/2 in the second equation:
- m/2 + m = 122
- (1/2)m + m = 122
- 3/2m = 122
- m = (2/3) * 122 = 244/3
- m = 81.333... (rounded to 81, because we cannot have a fraction of a minute)
Now we substitute m back into 2c = m to find c:
- 2c = 81
- c = 81/2
- c = 40.5 (rounded to 41 minutes, since we cannot have a fraction of a minute)
Finally, we already know u = 30 minutes. So the total minutes called is:
- Within Canada (c): 41 minutes
- To the U.S. (u): 30 minutes
- To Mexico (m): 81 minutes