F.3 MATHS
2014-11-13 7:34 pm
The sum of the hundreds digit and the tens-digit of athree- digit number is 13. If the hundreds digit and the tens digit areinterchanged, the new number is 90 less than the original number. It is giventhat the units digit of the original number is 4. Find the original number.
回答 (1)
2014-11-13 8:46 pm
✔ 最佳答案
Let the hundreds digit = atens digit = b
a + b = 13 ...........(1)
Original value of the number = 100a + 10b + 4
The new value of the number = 100b + 10a + 4
So (100b + 10a + 4) + 90 = (100a + 10b + 4)
90b - 90a = - 90
b - a = - 1............(2)
(1) + (2)
2b = 12
b = 6, so a = 7
the number is 764.
收錄日期: 2021-04-24 23:29:19
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20141113000051KK00025