The average age of mother and father is 28 years. The average age of mother, father and their child is 20 years. What is the age of the child ?
माता तथा पिता की औसत आयु 28 वर्ष है | माता, पिता तथा उनके बच्चे की औसत आयु 20 वर्ष है | बच्चे की आयु कितनी है ?

Options

A. 4 years / वर्ष
B. 3 years / वर्ष
C. 6 years / वर्ष
D. 5 years / वर्ष

Answer

To find the age of the child, we can follow these steps:

### Step 1: Calculate the total age of the mother and father
The average age of the mother and father is given as 28 years. Since there are 2 individuals (mother and father), we can calculate their total age using the formula for average:

\[ \text{Total age of mother and father} = \text{Average age} \times \text{Number of individuals} \]

\[ \text{Total age of mother and father} = 28 \times 2 = 56 \text{ years} \]

### Step 2: Calculate the total age of the mother, father, and child
The average age of the mother, father, and their child is given as 20 years. Since there are 3 individuals (mother, father, and child), we can calculate their total age:

\[ \text{Total age of mother, father, and child} = \text{Average age} \times \text{Number of individuals} \]

\[ \text{Total age of mother, father, and child} = 20 \times 3 = 60 \text{ years} \]

### Step 3: Find the age of the child
Now, we can find the age of the child by subtracting the total age of the mother and father from the total age of the mother, father, and child:

\[ \text{Age of child} = \text{Total age of mother, father, and child} - \text{Total age of mother and father} \]

\[ \text{Age of child} = 60 - 56 = 4 \text{ years} \]

### Final Answer:
The age of the child is **4 years**.

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