The difference between Chinky's and Minky's present age 3 years. Therefore, option 1. 3 years is correct.
let's tackle this step by step.
Given:
Ratio of Chinky's and Minky's present age = 4:5
Let Chinky's age be 4x and Minky's age be 5x.
Chinky's mother's present age = 9/2 times Minky's age 5 years ago.
Chinky's mother's age = 9/2 * (5x - 5)
Minky's mother's present age = 7/3 times Chinky's age after 3 years.
Minky's mother's age = 7/3 * (4x + 3)
After 15 years, the average age of Minky's mother and Chinky's mother is 55:
(Chinky's mother's age after 15 years + Minky's mother's age after 15 years) / 2 = 55
Let's calculate the ages of Chinky's and Minky's mothers after 15 years:
Chinky's mother's age after 15 years = 9/2 * (5x - 5) + 15
Minky's mother's age after 15 years = 7/3 * (4x + 3) + 15
So, the equation for the average age after 15 years becomes:
[(9/2 * (5x - 5) + 15) + (7/3 * (4x + 3) + 15)] / 2 = 55
Let's simplify this equation and solve for x:
[(45x - 45)/2 + (28x + 21)/3 + 30] / 2 = 55
[(135x - 135 + 56x + 42 + 180) / 6] = 110
(191x + 87) / 6 = 110
191x + 87 = 660
191x = 573
x = 573 / 191
x = 3
Now that we have found x = 3, let's find Chinky's age and Minky's age:
Chinky's age = 4x = 4 * 3 = 12 years
Minky's age = 5x = 5 * 3 = 15 years
Therefore, the difference between Chinky's and Minky's present age = 15 - 12 = 3 years.
Question
The ratio of the present age of Chinky and Minky is 4: 5 and the present age of Chinky's mother is 9/2 times Minky's age 5 years ago and the present age of Minky's mother is 7/3 times of Chinky's age after 3 years. If after 15 years the average age of Minky's mother and Chinky's mother is 55, then find the Difference between Chinky's and Minky's present age.
1. 3 years
2. 2 years
3. 4 years
4. 5 years