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
Answers
Answer:
Robert = 10 yrs, father = 40 yrs
Step-by-step explanation:
Let Robert present age be x.
Father present age = 4x.
Now,after 5 yrs ,
Robert age = x +5
Father = 4x + 5
Now,
After 5 yrs father is 3 times Robert.
So,
3(x + 5) = 4x + 5
3x + 15 = 4x + 5
15 - 5 = 4x - 3x
x = 10 yrs
Robert = 10 yrs
Father = 4 ☓ 10 = 40 yrs
Robert's Age = 10 years
Robert's Father Age = 40 years
Let us assume the age of Robert to be 'a' years.
If our assumption is correct then according to the question the age of Robert's father would be '4a'
Calculating Robert's age after 5 years:
= a + 5 years
Calculating Robert's fathers age after 5 years:
= 4a + 5 years
Framing A linear Equation According To The Question:
4a + 5 = 3(a + 5)
Solving The Linear Equation:
4a + 5 = 3a + 15
4a - 3a = 15 - 5
a = 10
Therefore, the value we obtain for 'a' is 10.
Therefore, the present age of Robert is 10 years because we have assumed the age of Robert as 'a'.
Calculating the present age of Robert's father:
= 4a
= 4 x 10
= 40 years
Therefore, the age of Robert's father is 40 years.