Kavita's age is eight years more than thrice the sum of the ages of her two grandsons who are twins. Nine years later, Kavita's age will be one year more than two times the sum of the ages of her two grandsons. What was the age of Kavita when her grandsons were born?

Correct option is A

Here, age of both the grandson will be same as they are twin.
Let the age of Kavita is x years and age of his grandson is y years.
The age of Kavita after 9 years = (x + 9) years
The age of Kavita's grandson after 9 years = (y + 9) years
Now, Kavita's age is eight years more than thrice the sum of the ages of her two grandsons, who are twins. So,
x = 3(y + y) + 8
x = 3(2y) + 8
x = 6y + 8 .....(1)
Also, nine years later, Kavita's age will be one year more than two times the sum of the ages of her two grandsons.
(x + 9) = 2[(y+9) + (y+9)] + 1
x + 9 = 2(2y + 18) + 1
x = 4y + 36 + 1 - 9
x = 4y + 28
Put the value x from equation (1) in the above equation,
6y + 8 = 4y + 28
6y - 4y = 28 - 8
2y = 20
y = 10 years
Put this value of y in equation (1),
x = 4(10) + 28
x = 40 + 28 = 68 years
So, the present age of Kavita is 68 years and her grandson is 10 years. Now, the before 10 years, her grandson were born.
Thus, the age of Kavita before 10 years, = 68 - 10 = 58 years