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:
Answer & explanation
Correct answer: option 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