Question

Robert's father is 4 times as old as Robert. After 5 years, the father will be three times as old as Robert. Find their present ages

Answer 1

Answer:

Step-by-step explanation:

Let the present age of Robert is x

So, the age of roberts father is 4*x=4x

After 5 yrs roberts father would be 3 times of his age.

So the age of robert after 5 yrs= x+5

And hence according to the problem,

3(x+5)=4x+5 { here we are equating roberts age with his father thats why there must be a 3 multiplied to roberts age such that while forming the equation roberts age and his fathers age should be equal}

Or, 3x+15=4x+5

Or, 4x-3x=15-5

Or, x=10.

Hence the age of Robert is 10 years . And while his fathers age is 40 years.