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Aptitude

Problems on Ages

Formulas For Ages

In these type of question are based on ages may be of one person or relative ages of two or more.

Basic Formulas on Ages

  • If the present age is x, then n times the age is nx.
  • If the present age is x, then age n years later/hence = x + n.
  • If the present age is x, then age n years ago = x – n.
  • The ages in a ratio a : b will be ax and bx.
  • If the present age is x, then 1n  \frac{1}{n} \ of age is xn \frac{x}{n} \

Important Concept on Problems on Ages
Concept 1

x years ago the age of A was $n_1$ times the age of B, and at present A’s age is $n_2$ times that of B, then;

A’s current = $\frac{\left (x)(t_{1}+ t_{2}\right )( y – 1)}{(x-y)} + t_{1}$ years

and, B’s current age =$\frac{\left ( n_{1} -1\right )x}{(n_{1}-n_{2})}$

Concept 2

The present age of A is $n_1$ times the present age of B. After x years, age of A becomes $n_2$ times the age of B, then;

A’s current = $\frac{\left ( n_{1} -1\right )n_{2}x}{n_{1}-n_{2}}$ years

and, B’s current age =$\frac{\left ( n_{1} -1\right )x}{(n_{1}-n_{2})}$

Concept 3

$t_1$ years ago, the age of A was X times the age of B and after $t_2$ years age of A becomes Y times the age of B, then;

A’s current = $\frac{\left ( n_{1} -1\right )n_{2}x}{n_{1}-n_{2}}$ years

and, B’s current age =$\frac{t_{2}(y – 1)+t_{1}(x – 1)}{x – y}$

Concept 4

The sum of present ages of A and B is X years, $t$ years after, the age of A becomes Y times the age of B, then;

A’s current = $\frac{xy + t(y-1)}{y +1}$ years

and, B’s current age =$\frac{x- t(y-1)}{y+1}$

Concept 5

The ratio of the present ages of A and B is p: q and after $t$ years, it becomes $r : s$, then;

A’s current = $\frac{pt(r-s)}{ps-qr}$ years

and, B’s current age =$\frac{qt(r-s)}{ps-qr}$

Concept 6

TThe sum of present ages of A and B is X years, $t$ years ago, the age of A was Y times the age of B, then;

A’s current = $\frac{xy + t(y-1)}{y +1}$ years

and, B’s current age =$\frac{x+ t(y-1)}{y+1}$