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The ages of two friends is in the ratio 5:6. After how many years will the ages be in the ratio 7:8? a)20year b)12year c)15year d)10year

+7 votes
asked Oct 14, 2014 in TCS by Pushpa Kumari 2 flags

1 Answer

+3 votes
let the ages are 5x, 6x. Then after K years their ages are 7:8
So $\displaystyle\frac{{5x + k}}{{6x + k}} = \frac{7}{8}$
$ \Rightarrow 40x + 8k = 42x + 7k$
$ \Rightarrow$ k = 2x
Here we got an equation which gives multiple answers. For example, If x = 10, then after 20 years their ages are in 7:8 ratio. If x = 6 then after 12 years.  

So all even numbers satisfies this.
answered Oct 15, 2014 by Campusgate 1 flag
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