Question

After 15 years Prem will be four times as old as he was 6 years ago. Find his present age.​

Answer 1

Step-by-step explanation:

after 15 year prem age x+15

according to question

x+15 =4(x-6)

x+15=4x-24

x-4x=-24-15

-3x=- 39

x=39/3

x=13

Answer 2

Given:

Age of Prem after 15 years = $P+15$

Age of Prem 6 years ago = $P-6$

To find:

Present age of Prem.

Solution:

Let the present age of Prem be $P$.

According to the problem, 6 years ago Prem's age was $P-6$. Four times of this age will be equal to Prem's age after 15 years from his current age,i.e.,

$4(P-6)=P+15$

$4P-24=P+15$

$4P-P=24+15$

$3P=39$

$P=\frac{39}{3}=13$ years

Rechecking,

Prem's age 6 years ago = $13-6=7$ years

Four times the age of Prem before 6 years = $4*7=28$

Prem's age after 15 years = $15+13=28$

Hence, Prem's age after 15 years = Four times the age of Prem before 6 years

The present age of Prem is 13 years.