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15 years ago the average age of a family of four members was 40 years. Two children were born in this span of 15 years. The present average of the family remains unchanged. Among the two children who were born during the 15 years, if the older child at present is 8 years older than the younger one, what is the ratio of the present age of the older child to the present age of the younger Child?
  • a)
    9:4
  • b)
    7:3
  • c)
    7:6
  • d)
    7:4
  • e)
    9:5
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
15 years ago the average age of a family of four members was 40 years....
15 years ago Total age of a family of four members = 160
Sum of the Present age of a family of four members = 160 + (15*4) = 220
Sum of the Present age of a family of six members = 40*6 = 240
x+x+8 = 20
x=6
present age of the older child to the present age of the younger Child = 14:6 = 7:3
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Most Upvoted Answer
15 years ago the average age of a family of four members was 40 years....
Given:
- 15 years ago, average age of a family of four was 40 years.
- In the span of 15 years, two children were born.
- Present average age of the family remains unchanged.
- The older child is 8 years older than the younger one.

To Find: Ratio of the present age of the older child to the present age of the younger child.

Solution:
Let's assume the present age of the younger child is y years.
So, the present age of the older child will be (y+8) years.

15 years ago, the average age of the family of four was 40 years.
So, the sum of their ages 15 years ago = 40 x 4 = 160 years.

In the span of 15 years, two children were born.
So, the total number of family members now = 4+2 = 6.

The present average age of the family remains unchanged.
Let's assume the present average age of the family is x years.

So, the sum of their present ages = 6x years.

We know that the sum of their ages 15 years ago = 160 years.
So, the sum of their present ages = (160 + 6 x 15) years = 250 years.

Therefore, 6x = 250
x = 41.67

Present age of the younger child = y
Present age of the older child = y+8

Ratio of their present ages = (y+8)/y

Substituting the value of x in terms of y:
6x = 250
y + (y+8) + (41.67 x 4) x 4 = 250
2y + 33 + 166.68 = 250
2y = 50.32
y = 25.16

Therefore, the present age of the younger child = 25.16 years.
And the present age of the older child = 25.16 + 8 = 33.16 years.

Ratio of their present ages = (33.16/25.16) = 7:3

Hence, the correct option is (B) 7:3.
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Community Answer
15 years ago the average age of a family of four members was 40 years....
15 years ago Total age of a family of four members = 160
Sum of the Present age of a family of four members = 160 + (15*4) = 220
Sum of the Present age of a family of six members = 40*6 = 240
x+x+8 = 20
x=6
present age of the older child to the present age of the younger Child = 14:6 = 7:3
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15 years ago the average age of a family of four members was 40 years. Two children were born in this span of 15 years. The present average of the family remains unchanged. Among the two children who were born during the 15 years, if the older child at present is 8 years older than the younger one, what is the ratio of the present age of the older child to the present age of the younger Child?a)9:4b)7:3c)7:6d)7:4e)9:5Correct answer is option 'B'. Can you explain this answer?
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15 years ago the average age of a family of four members was 40 years. Two children were born in this span of 15 years. The present average of the family remains unchanged. Among the two children who were born during the 15 years, if the older child at present is 8 years older than the younger one, what is the ratio of the present age of the older child to the present age of the younger Child?a)9:4b)7:3c)7:6d)7:4e)9:5Correct answer is option 'B'. Can you explain this answer? for Quant 2024 is part of Quant preparation. The Question and answers have been prepared according to the Quant exam syllabus. Information about 15 years ago the average age of a family of four members was 40 years. Two children were born in this span of 15 years. The present average of the family remains unchanged. Among the two children who were born during the 15 years, if the older child at present is 8 years older than the younger one, what is the ratio of the present age of the older child to the present age of the younger Child?a)9:4b)7:3c)7:6d)7:4e)9:5Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for Quant 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for 15 years ago the average age of a family of four members was 40 years. Two children were born in this span of 15 years. The present average of the family remains unchanged. Among the two children who were born during the 15 years, if the older child at present is 8 years older than the younger one, what is the ratio of the present age of the older child to the present age of the younger Child?a)9:4b)7:3c)7:6d)7:4e)9:5Correct answer is option 'B'. Can you explain this answer?.
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