Question

I am as much older than my brother who is $10$ years as I am younger than my father who is $70$years. How old am I?
$A)40$years
$B)30$years
$C)20$years
$D)10$years

Answer 1

Hint: First we have to define what the terms we need to solve the problem are.
Since we have to find the original age of the person X (unknown) and there is some information given in the question to solve this problem further.
Using the mathematical approach first converts the given problem into mathematical terms and then we can simply solve by using any of the formulas like elimination or substitution method.

Complete step by step answer:
Let us fix the value of the person that we need to find as X. then from the given question first convert the statement into an equation as X is as much older than his brother ten years as X is younger can be framed the equation into $X - 10$.
Also, the same X is seventy years younger than his father and hence we get the conversion as $70 - X$.
Since these two statements are equivalent (related same), thus both the expressions compare X only, so we will combine the equation into one term.
Thus, get $X - 10 = 70 - X$ this equation can be solved by using the canceling the values on both sides or crossing the numbers on the right-hand side and values on the left-hand side;
Thus, we get $X - 10 = 70 - X \Rightarrow 2X = 10 + 70$ further solving we get $X = \dfrac{{80}}{2} \Rightarrow 40$ (by division operators), and hence the value of X is forty years old.

So, the correct answer is “Option A”.

Note: Since we have to apply the correct values to the given statements as an equation like$70 - X$ for the father who is $70$years means seventy minus the X and younger means like a brother who is $10$years as X is $X - 10$.
Suppose if we substitute the values as$X - 70$ then we will get the wrong answer in the calculation as above.
There is no possibility of getting other options like B, C, D except there is a calculation mistake.