Question

rithikas present age is 4 times her son's present age and two fifth of her father's present age.The average present age of all of them is 40 years. find the sum of rithikas son's present age and rithikas father present age?​

Answer 1

Answer:

78 years

Step-by-step explanation:

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Answer 2

Given:

The average present age of all of them is 40 years

To find:

The sum of Rithika's son's present age and Rithika's father's present age

Solution:

The sum of Rithika's son's present age and Rithika's father's present age is 88 years.

We can find the sum by following the given steps-

Let us assume that the present age of Rithika is X, her son's present age is Y, and her father's present age is Z.

We are given that Rithika's present age is 4 times her son's age.

So, X=4Y

X/4=Y

Also, her present age is 2/5th of her father's age.

X=2/5×Z

5X=2Z

5X/2=Z

Now, the average present age of all of them is 40 years.

The average present age of all of them=(Present age of Rithika+Present age of son+Present age of father)/3

40=(X+Y+Z)/3

X+Y+Z=40×3

X+Y+Z=120

Substituting the value of Y and Z, we get

X+X/4+5X/2=120

4X/4+X/4+10X/4=120

15X/4=120

X=120×4/15

X=480/15

X=32 years

Now we will use the value of X to find Y and Z.

Y=X/4=32/4=8 years

Z=5X/2=5×32/2=5×16=80 years

The sum of Rithika's son's and father's present age=Y+Z

=8+80

=88 years

Therefore, the sum of Rithika's son's present age and Rithika's father's present age is 88 years.