Multiple choice

Twenty years ago the age of father is four times the age of son. After 20 years from now the ratio of father's age and son's age will be 8:5. What is sum of their present ages? 20 वर्ष पहले पिता की आयु पुत्र की आयु का चार गुना थी। अब से 20 वर्ष बाद पिता और पुत्र की आयु का अनुपात 8 : 5 है। दोनों की वर्तमान आयु का योग कितना है?

  1. 100 years 100 वर्ष

  2. 120 years 120 वर्ष

  3. 90 years 90 वर्ष

  4. 80 years 80 वर्ष

  5. None of these इनमें से कोई नहीं
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let present ages be F (father) and S (son). 20 years ago: F-20 = 4(S-20), so F = 4S - 60. After 20 years: (F+20)/(S+20) = 8/5, so 5(F+20) = 8(S+20), giving 5F - 8S = 60. Substituting F = 4S - 60: 5(4S-60) - 8S = 60, so 20S - 300 - 8S = 60, giving 12S = 360, S = 30. Then F = 4(30) - 60 = 60. Sum = 60 + 30 = 90. The claimed answer C (90 years) is correct.

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