Seven years ago, the ages (in years) of A and B were in the ratio 4 : 5 and 7 years hence, their ages will be in the ratio 5 : 6. What will be the ratio of their ages 5 years from now?
Let Age of A = a, And ages B = bÂ
then according to question $$\dfrac {a-7}{b-7} = \dfrac {4}{5}$$
$$\Rightarrow 5a - 35 = 4b - 28 $$
$$\Rightarrow 5a -4b = 7 $$Â Â ........ equestion (A)
again second case $$\dfrac{a + 7 }{b+7} = \dfrac {5} {6} $$
$$\Rightarrow 6a + 42 = 5b + 35 $$
$$\Rightarrow 6a - 5b = 7Â $$Â Â ......... equestion (B)
then Substract B from AÂ
so $$ 5a - 4b + 6a - 5b = 0 $$
$$\Rightarrow 11 a = 9b $$
$$\Rightarrow a = \dfrac {9}{11}b $$Â ...... equestion (C)
put the value in the equestion B
so 55 b - 54b = 77Â
b = 77 so we put the value of b = 77 in equestion (C)
$$a = \dfrac {9}{11}\times 77 $$
a = 63Â
then again $$\dfrac {a +5}{b+ 5}$$
$$\Rightarrow \dfrac {63+5}{77 +5}$$
$$\Rightarrow \dfrac {68}{82}$$
$$\Rightarrow \dfrac {34}{41}$$ Ans
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