In an alloy, aluminium and tin are in the ratio of 4 : 5. In the second alloy, the ratio of same elements is 4 : 7. If equal quantities of these two alloys be mixed to form a new alloy, then what will be the ratio of both of these elements in the new alloy?

Ratio of aluminium and tin in first alloy = 4 : 5

Ratio of aluminium and tin in second alloy = 4 : 7

Let quantity of both alloys taken = L.C.M. (9,11) = 99 units

=> Aluminium in first alloy = $$\frac{4}{(4+5)}\times99=44$$ units

Tin present in first alloy = $$99-44=55$$ units

Similarly, aluminium in second alloy = $$36$$ units and tin = $$63$$ units

$$\therefore$$ Ratio of aluminium and tin in the new alloy = $$\frac{(44+36)}{(55+63)}$$

= $$\frac{80}{118}=\frac{40}{59}$$

=> Ans - (D)