Correct option is C
Given:
After 20 years: Father's age = 2 × Son's age
5 years ago: Father's age = 7 × Son's age
Solution:
Let the present age of the Father be F and the present age of the Son be S.
According to the first condition, after 20 years:
F + 20 = 2 × (S + 20)
F + 20 = 2S + 40
F - 2S = 20 --- (Equation 1)
According to the second condition, 5 years ago:
F - 5 = 7 × (S - 5)
F - 5 = 7S - 35
F - 7S = -30 --- (Equation 2)
We will subtract Equation 2 from Equation 1.
(F - 2S) - (F - 7S) = 20 - (-30)
5S = 50
S = 10
The present age of the Son is 10 years.
Substitute S in Equation 1 to find the Father's age.
F - 2 × 10 = 20
F - 20 = 20
F = 40
The present age of the Father is 40 years.
Final Answer
So the correct answer is (c)
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