# need 式

1.Mr.chung 's age is 8 times his daughter's age this year. 12 years later , the sum of their age will be 87. how old is Mr.chung now?

2.A father 's age is 3 times his son's age 7 years ago.if the sum of their age is 70 now. Find their ages 7 years ago.

need 式

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1. Mr. Chung 's age is 8 times his daughter's age this year. 12 years later , the sum of their age will be 87. how old is Mr. Chung now?

Let x be the age of Mr. Chung now.

His daughter's age now is x/8.

12 years later,

(x + 12) + (x/8 + 12) = 87

9x/8 + 24 = 87

9x/8 = 63

x/8 = 7

x = 56

Mr. Chung is 56 years old now.

2. A father 's age is 3 times his son's age 7 years ago.if the sum of their age is 70 now. Find their ages 7 years ago.

Let x be the son's age 7 years ago.

The father's age 7 years ago is 3x.

Now, the ages of the son and the father are respectively x+7 and 3x+7.

(x + 7) + (3x + 7) = 70

4x + 14 = 70

4x = 56

x = 14

Therefore, 7 years ago, the son's age was 14 and the father's age was 14*3 = 42.

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