Max comes from Belize, one of the few countries to use the month/day/year form for writing dates rather than day/month/year. His date of birth was written 5/4/1996 but mistaken to be 5th April instead of 4th May. How many days in a year give a valid but different date when read the wrong way?
Correct answer: C. 132
- A. 66
- B. 72
- C. 132
- D. 144
Explanation
Since Max's date of birth was mistaken to be 5th April instead of 4th May, we can assume that the day and month were swapped. Therefore, the mistaken date would be 4/5/1996.For a valid but different date to be formed when read the wrong way, the month and day must be within the range of valid values for months and days.If we swap the day and month of a date, we get a valid but different date when both the day and month are within the range of valid values.For example, if the original date is 1/7/2023 (1st July 2023), swapping the day and month would give us 7/1/2023 (7th January 2023), which is a valid but different date.In each month, the first 12 days are the ones that will give a valid date when day and month can be switched to still obtain a valid date. However, in each month there are only 11 dates that can give valid but different date, because one of the first 12 dates will hold the same day and month, example 2nd February is 2/2 so swapping it won't make a difference.Taking the example of February to calculate:2/1, 2/3, 2/4, 2/5, 2/6, 2/7, 2/8, 2/9, 2/10, 2/11, 2/122/13--- 2/31 can't be misread.Same is the case of rest of the 11 months.So the number of dates that can be misread are: 11 × 12= 132Therefore, the answer is C) 132.
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