Question

After 15 years mary's age will be 4 times of her present age find her present age​

Answer 1

Answer:

$\underline{\boxed{\textsf{Present age = 5yrs }}}$

Step-by-step explanation:

$\underline{\underline{\textsf{Given that..}}}$

After 15yrs Mary's age will be 4 times of her present age ... and now we need to find her present age

$\underline{\underline{\textsf{Solution...}}}$

$\underline{\textsf{Let, the}}$

$\mathsf{Present\:age \:=\: x}$ ------- eq(1)

$\therefore \textsf{Age after 15yrs}$ ------- eq(2)

$\mathsf{Age\:After\: 15yr \: =\: x + 15}$

$\underline{\textsf{According to question..}}$

Age after 15 yrs = 4 times her present age

that is

$\implies \textsf{x + 15 = 4(x)}$

$\implies \mathsf{x\:+\:15\:=4x}$

Taking X from LHS to RHS we have...

$\implies \mathsf{15\:=\: 4x\: -\: x }$

$\implies \mathsf{15\:=\: 3x }$

That is ...

$\implies \mathsf{3x = 15 }$

$\implies \mathsf{x\: =\: \dfrac{15}{3} \:= \:5 }$

$\underline{\mathsf{Putting\: value \:of \:x \:=\: 3 \:in\: equation\: (1) \:we \:have... }}$

$\mathsf{Present\:age \:=\: x\:=\:5 }$

$\underline{\textbf{Hence the required answer is }}$

$\boxed{\boxed{\textbf{Present age = 5yrs}}}$