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 =
4
(4+5)
×99=44 units Tin present in first alloy = 99−44=55 units Similarly, aluminium in second alloy = 36 units and tin = 63 units ∴ Ratio of aluminium and tin in the new alloy =