My younger sister’s age today is $$3$$ times, what will it be $$3$$ years from now minus $$3$$ times what her age was $$3$$ years ago. Find out her present age.

Question

Vedantu Content Team · Accepted Answer

Hint:To solve this question we start by assuming the younger sister’s age to be a variable. It could be any variable let’s say x. After that we can form a linear equation to determine what her present age would be. We form this linear equation by using the things given to us in the question. Complete step by step answer: Let’s assume the present age of the younger sister to be x years old. As given in the question we can start by saying that the age of the younger sister $$3$$ years from now will be $$x+3$$ when tried to write in the form of an expression. Similarly we can also say that the age of the younger sister $$3$$ years ago used to be $$x-3$$ if tried to write in the form of an expression.Now in the question it is also said that the sisters present age can be expressed in the way that her age at present that is x is equal to $$3$$ times what it will be in three years which we found out can be expressed as $$x+3$$ and subtract it from $$3$$ times what her age used to be $$3$$ years ago which we also found out to be $$x-3$$ , now trying to write this in a form a linear equation we get that;$$x=3(x+3)-3(x-3)$$Now we want to find $x$ here so we start by opening both brackets and multiplying, $$x=3x+9-3x+9$$Now subtracting and adding the terms we can see that the x terms on the right times will be cancelled and we get,$$\therefore x=18$$Hence we can say that the younger sister’s current age is $$18$$ years old.Note: We can always solve any questions like this with any condition given by converting the problem statement in the form of a linear equation and then solve and simplify it to get the answer needed. Some statements that will make this questions easier is-If age is $x$ then age $n$ years later will be $$=x+n$$-If age is $x$ now, then $n$ times age will be$$=nx$$-If age is $x$ then age $n$ years before it was $$=x-n$$

My younger sister’s age today is \[3\] times, what will it be \[3\] years from now minus \[3\] times what her age was \[3\] years ago. Find out her present age.