50 g of an alloy of gold and silver contains 80% gold (by weight). The

1.	50 g of an alloy of gold and silver contains 80% gold (by weight). The quantity of gold, that is to be mixed up with this alloy, so that it may contain 95% gold is (a) 200 g (b) 150 g (c) 50 g (d) 10 g
Answer» (b) 150 g In 50 gm of an alloy of gold and silver, the quantity of gold = 40 gm and the quantity of silver = 10 gm, Let x gm of gold be mixed in 50 gm of an alloy of gold and silver such that quantity of gold becomes 95%. Then, 40 + x = 95% of (x + 50) 40 + x = \(\frac{19}{20}\)( x+ 50) \(\Rightarrow\) 800 + 20x = 19x + 950 \(\Rightarrow\) x = 150.

50 g of an alloy of gold and silver contains 80% gold (by weight). The quantity of gold, that is to be mixed up with this alloy, so that it may contain 95% gold is (a) 200 g (b) 150 g (c) 50 g (d) 10 g

Answer»

(b) 150 g

In 50 gm of an alloy of gold and silver, the quantity of gold = 40 gm and the quantity of silver = 10 gm,

Let x gm of gold be mixed in 50 gm of an alloy of gold and silver such that quantity of gold becomes 95%.

Then, 40 + x = 95% of (x + 50)

40 + x = \(\frac{19}{20}\)( x+ 50)

\(\Rightarrow\) 800 + 20x = 19x + 950

\(\Rightarrow\) x = 150.