The sum of the present ages of father and son is 68 years. 8 years ago, the…
2019
The sum of the present ages of father and son is 68 years. 8 years ago, the ratio of their ages was 12 : 1. The ratio of their ages after 4 years will be
- A.
16 : 5
- B.
13 : 2
- C.
15 : 4
- D.
14 : 3
Attempted by 8 students.
Show answer & explanation
Correct answer: C
Let the present age of the father be F years and the son be S years.
Given: F + S = 68. (Equation 1)
8 years ago, father's age was F - 8 and son's age was S - 8.
Given: (F - 8) / (S - 8) = 12 / 1
So, F - 8 = 12(S - 8)
F - 8 = 12S - 96
F = 12S - 88 (Equation 2)
Substitute Equation 2 into Equation 1:
12S - 88 + S = 68
13S = 156
S = 12
Then F = 68 - 12 = 56
After 4 years, father's age = 56 + 4 = 60, son's age = 12 + 4 = 16.
Ratio = 60 : 16 = 15 : 4
हिन्दी उत्तर:
माना पिता की वर्तमान आयु F वर्ष और पुत्र की आयु S वर्ष है।
दिया गया है: F + S = 68. (समीकरण 1)
8 वर्ष पूर्व, पिता की आयु F - 8 और पुत्र की आयु S - 8 थी।
दिया गया है: (F - 8) / (S - 8) = 12 / 1
इसलिए, F - 8 = 12(S - 8)
F - 8 = 12S - 96
F = 12S - 88 (समीकरण 2)
समीकरण 2 को समीकरण 1 में रखने पर:
12S - 88 + S = 68
13S = 156
S = 12
तब F = 68 - 12 = 56
4 वर्ष बाद, पिता की आयु = 56 + 4 = 60, पुत्र की आयु = 12 + 4 = 16।
अनुपात = 60 : 16 = 15 : 4