In an alloy the ratio of copper and zinc is 5 : 2. If 1.250 kg of zinc is mixed in 17.5 kg of alloy then the ratio of copper and zinc in the alloy will be:

2 : 1

Ratio of copper and zinc in alloy = 5 ∶ 2

If 1.250 kg of zinc is mixed

Let Copper and zinc in 1 kg alloy be 5m and 2m respectively. in 17 kg 500 gm of alloy.

⇒ Weight of alloy before zinc addition = 17 + \(\frac{1}{2}\) = \(\frac{35}{2}\) kg

⇒ 7m = \(\frac{35}{2}\)

⇒ m = \(\frac{5}{2}\)

⇒ Copper in alloy = 5 × (\(\frac{5}{2}\)) = \(\frac{25}{2}\) kg

⇒ Zinc in alloy = 2 × (\(\frac{5}{2}\)) = 5 kg

⇒ New amount of zinc after addition = 5 + 1.250 = 6.250 kg

⇒ Ratio of copper to zinc in alloy = (\(\frac{25}{2}\)) ∶ (6.250) = 25 ∶ 12.5 = 2 ∶ 1