Question

The current age of grandmother of Runa can be obtained by revising the digits of current age of Runa . Also Runa is 54 years younger than her grandmother . Determine the age of Runa 7 years ago

Answer 1

Tip: Solve it by Hit & Trial method.

Step-by-step explanation:

Given-

1. Age of grandmother is obtained by reversing the digits of age of Runa.

2. Difference between the age of grandmother and Runa is 54 years.

To find- We have to find the age of Runa 7 years ago.

Solution- To find the age of Runa 7 years ago, we have to first find her age at present by using the given conditions.

1. So, let's assume Runa's age to be XY(where X&Y represents digits), which means that grandmother's age will be YX(where Y&X represents digits).

2. Let XY be a, and YX be b (a&b are variables here representing age).

3. Now, it's given that difference between their ages is 54 years. Forming it into an equation we get:-

b - a = 54 (b must be greater than a because b represents grandmother's age)

4. Now comes the most important step, where we will use the Hit&Trial method. Understand it very carefully:-

A. Let's assume age of Runa be 16 ( You will ask me why to consider this age and not any other, my answer would be, because a kid having a grandmother will most probably lie in the age group of 15-20 years)

This would mean the age of Grandma will be 61.

Now, calculating the difference between their ages we get,

61 - 16 = 45 years, which does not match our given conditions.

B. Now consider Runa's age to be 17, the Grandma will age 71 years.

Now getting the difference between their ages,

71 - 17 = 54 years, which matches the given conditions.

Here, we got our answer, which is:-

Runa's age, a= 17 years

Grandmother's age, b= 71 years.

But if we didn't get the answer here, we will continue to apply hit&trial method by considering Runa's age to be between 15-20 years.

5. Now, comes the last part, to find the age of Runa 7 years ago,

we will simply subtract 7 years from current age of Runa which is 17 years.

We will get:-

17 - 7 = 10 years.

Therefore, the final answer is 10 YEARS.