Multiple choice

The ratio of present age of A, B and C is 4 : 5 : 6. If the product of age of A and C is 36 more than product of age of A and B. What is the age of C at present. A, B और C की वर्तमान आयु का अनुपात 4 : 5 : 6 है यदि A और C की आयु का गुणनफल A तथा B के आयु के गुणनफल से 36 अधिक है तो C की वर्तमान आयु ज्ञात कीजिये।

  1. 30 years/वर्ष

  2. 33 years/वर्ष

  3. 15 years/वर्ष

  4. 18 years/वर्ष
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D Correct answer
Explanation

Let ages be 4k, 5k, 6k. Given: (A × C) = (A × B) + 36. So 4k × 6k = 4k × 5k + 36. 24k² = 20k² + 36. 4k² = 36. k² = 9. k = 3. C's age = 6k = 6 × 3 = 18 years. Option A (30) would be if k=5. Option B (33) doesn't fit the ratio. Option C (15) would be if k=2.5.

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