Two brothers share a flock of x sheep. They take the sheep to the market and sell each sheep for x. At the end of the day they put the money from the sales on the table to divide it equally. All money is in 10 bills, except for less than ten excess 1 bills. One at a time they take out 10 bills. The brother who draws first also draws last. The second brother complains about getting one less 10 bill so the first brother offers him all the 1 bills. The second brother still received a total less than the first brother so he asks the first brother to write him a check to balance the things out. How much was the check?
Solution
从题目可知：
/[x^2 = 10a+b
/]
其中 /(1/leq b/leq 9/)。 其次，我们还得知 /(a/%2=1/)，因为轮流拿10的时候，第一个人拿了第一张和最后一张。由于和为平方，所以简单枚举一下可以发现满足条件的只有 /(16, 36/).
不论哪一种，最后个位数都是 /(6/), 所以 /(check = 2/).
原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/280044.html