The weights of three friends are in the ratio 7 : 8 : 9. If each gains 5 kg, the new ratio becomes 12 : 13 : 14. What is the original weight of the heaviest friend?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 9 kg.
Let original weights are 7x, 8x, and 9x
New weights are 7x + 5, 8x + 5, and 9x + 5
(7x+5)/(8x+5) = 12/13
⇒ 91x + 65 = 96x + 60
⇒ 5 = 5x
⇒ x = 1
Heaviest original weight = 9x = 9 kg