Question

after 15 years, roy will be 4 times as old as he is now. determine the his present age

Answer 1

Answer:

The present age of Roy is 5 years.

Step-by-step explanation:

Given :

Roy will turn 4 times his present age after 15 years

To find :

Their present ages

Solution :

Let the present age be as y

Age after 15 years = (y + 15)

According to the question, Roy will turn 4 times his present age after 15 years

$\sf{\implies} \: (y + 15) = 4y \\ \\ \sf{\implies} \:4y - y = 15 \\ \\ \sf{\implies} \:3y = 15 \\ \\ \sf{\implies} \:y = \dfrac{15}{3} \\ \\ \sf{\implies} \:y = 5$

Present age = 5 years

$\therefore$ The present age of the boy is 5 years.

Answer 2

$\sf \purple{ \underline{ \large { \: Solution : \: \: }} }$

Let ,

The present age of roy be x

After 15 years ,

Roy's age = 4 × Roy's present age

Thus ,

$\sf \hookrightarrow ( x + 15 ) = 4(x) \\ \\ \sf \hookrightarrow</p><p>x + 15 = 4x \\ \\ \sf \hookrightarrow</p><p>3x = 15 \\ \\ \sf \hookrightarrow </p><p>x = 5</p><p>$

Hence , the present age of roy is 5 years

$\sf \purple{ \underline{ \large { \: Verification : \: \: }} }$

If our answer makes LHS = RHS in the equation then our answer is absolutely correct

$\implies (5 + 15) = 4(5) \\ \\ \implies 20 = 20$

$\star$LHS = RHS

Hence verified