maths F.2 easy (急)

scyyy

2008-08-07 10:33 pm

1.Sam got $40 more pocket money than Joe last week. If their father gives each of them $20 more this week, Sam will get twice as much as Joe. How much does each of them get this week?

2.The total age of a woman and her son is 48. The woman was 7 times as old as his son 4 yeas ago. How old is her son now?

3.Last year Mr. Chan was 3 times as old as his daugher, and the sum of their present age is 66. Find the present age of Mr. Chan

回答 (1)

用戶7788

2008-08-07 11:14 pm

✔ 最佳答案

1/ Sam : $80, Joe $40 (this week)
2/ Son - 6 years old
3/ Pressnt age of Mr.Chan : 49

2008-08-07 15:26:20 補充：
So sorry that for question 2 answer should be 9 years old

2008-08-07 17:57:12 補充：
equation below

1/ let Joe got $y last week, in this week, Joe gets $(y+20) and Sam gets $(y+40+20)
2(y+20) = y+60
2y+40 = y+60
y = 20

2008-08-07 17:57:23 補充：
2/ Let y be the present age of the son, mun is (48-y) years old,
4 years ago....
7(y-4) = (48-y-4)
7y-28 = 44-y
8y = 72
y = 9

2008-08-07 17:57:33 補充：
3/ let y be the present age of the daughter .
3(y-1) = 66-y-1
3y-3 = 65-y
y = 17
daughter's present age is 17, her father 's age last year is 48, so this year is 49.

參考: My knowledge

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