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Spending money according to dates
Problem 1Mr. X had a habit of spending money according to dates. For example, if date was 19 he was spending $19, and if date was 15 he was spending $15.
One night he calculated total spending of 5 consecutive days - Monday to Friday, and he found that he spent $61 in 5 days.
So, identify the dates. (Assume that everyday spending is integer number of dollars).
Answer. There is only one solution:
27 and 28 of February and 1, 2, and 3 of March.
(27 + 28 + 1 + 2 + 3 = 61).
Solution
If these days would be inside one month, then the dates are (x-2), (x-1), x, (x+1) and (x+2), where x is the date in the middle of 5 days.
Then the sum must be multiple of 5, since
(x-2) + (x-1) + x + (x+1) + (x+2) = 5x.
But the integer 61 is not multiple of 5. Contradiction.
Hence, the dates are partly the end of some month and the beginning of the next month.
Then, it is easy to check that the dates 27, 28, 1, 2 and 3 satisfy the condition 27 + 28 + 1 + 2 + 3 = 61.
Next, it is easy to see that there is no other solution.
Problem 2Same problem if Mr. X spent $63 in 5 consecutive days. Identify the dates. Solve the problem yourself.
Problem 3Next time Mr. X's spending was $90 of 6 consecutive days - Monday to Saturday.
Identify the dates. Solve the problem yourself.
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