The ratio of copper and zinc in a 63 kg alloy is 4: 3. Some amount of copper is extracted from the alloy, and the ratio becomes 10: 9. How much copper is extracted?

6 Kg

Ratio of copper and zinc = 4  :  3

Quantity of alloy = 63 kg

ATQ,

( 4 + 3 )R = 63

7R = 63

1R = 9 kg

So, Amount of copper in alloy = 4R = 4 x 9 = 36 kg

Amount of zinc in alloy = 3R = 3 x 9 = 27 kg

Now, Some amount of copper is extracted and ratio of copper and zinc becomes = 10 : 9

As, Quantity of zinc remains same.

So,  9R = 27

1R = 3 kg

Quantity of copper left = 10R = 10 x 3 = 30G

Extracted amount of copper = 36 - 30 = 6 kg