10 years ago the average age of a family of 4 members was 24 years. No...
Let total age of family be G years.
10 years ago, total age = G – 10 × 4 = G – 40
According to question
G = 24 × 4 + 40 = 136 years
Let present age of youngest child = x
Present age of older child = x + 2
2x + 138 = 24 × 6
2x = 144 – 138 = 6
∴ x = 6/2 = 3 years
∴ Present age of youngest child = 3 years
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10 years ago the average age of a family of 4 members was 24 years. No...
Understanding the problem:
We are given that 10 years ago, the average age of a family of 4 members was 24 years. Now two more babies were born with an age difference of 2 years, and the average age of the family is still 24. We need to determine the present age of the youngest child.
Solution:
Let's assume the present age of the youngest child is x years.
Step 1: Determine the sum of ages 10 years ago:
10 years ago, the average age of the family was 24 years. Therefore, the sum of ages of the family 10 years ago would be 24 * 4 = 96 years.
Step 2: Determine the sum of ages at present:
Now, let's consider the present age of the two babies. We know that the age difference between them is 2 years. So, the present age of the older baby would be (x + 2) years. The present age of the youngest baby would be x years.
Therefore, the sum of ages at present would be (x + (x + 2) + 24 + 24).
Step 3: Use the given information to form an equation:
According to the problem, the average age of the family is still 24 at present. So, we can write the equation as:
(sum of ages at present) / (number of family members) = 24
Substituting the values, we get:
((x + (x + 2) + 24 + 24) / 6) = 24
Step 4: Solve the equation:
Simplifying the equation, we get:
(2x + 50) / 6 = 24
Multiplying both sides by 6, we get:
2x + 50 = 144
Subtracting 50 from both sides, we get:
2x = 94
Dividing both sides by 2, we get:
x = 47
Step 5: Determine the present age of the youngest child:
Therefore, the present age of the youngest child is 47 years.
Hence, option C (3 years) is the correct answer.