簡單數學一題
2007-11-09 4:14 am
In 17 years a man's age will be twice his age 13 years ago.What is his present age?
回答 (3)
2007-11-09 4:19 am
✔ 最佳答案
Let his age be X now.x+17=2(x-13)
x+17=2x-26
x=43
So his age is 43 now.
2007-11-09 4:22 am
Let the man's present age be x.
Then his age after 17 years = x + 17
and his age 13 years ago = x - 13.
2 (x - 13) = x + 17
=> 2x - 26 = x + 17
=> 2x - x = 17 + 26
=> x = 43
The man's present age is 43.
Then his age after 17 years = x + 17
and his age 13 years ago = x - 13.
2 (x - 13) = x + 17
=> 2x - 26 = x + 17
=> 2x - x = 17 + 26
=> x = 43
The man's present age is 43.
2007-11-09 4:18 am
17*2-13
=34-13
=21
=34-13
=21
收錄日期: 2021-04-13 14:23:03
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