20 litres of a mixture contains 20% alcohol and the rest water. If 4 litres of water be mixed in it, the percentage of alcohol in the new mixture will be

• 
• 

• 25%

• 

B.

Quantity of alcohol in 20 litres of mixture = 20% of 20 = 4 litres
Quantity of water in 20 litres of mixture = (20 - 4) = 16 litres
On adding 4 litres of water in mixture, 
New quantity of water  = (16 + 4)  = 20 litres
New quanity of mixture = 24 litres
∴  Required per cent

300 grams of sugar solution has 40% of sugar in it. How much sugar should be added to make it 50% in the solution?

• 40 gram

• 10 gram

• 60 gram

• 80 gram

49 kg of blended tea contains Assam and Darjeeling tea in the ratio 5 : 2. Then the quantity of Darjeeling tea to be added to the mixture to make the ratio of Assam to Darjeeling tea 2 : 1 is

• 4.5 kg

• 3.5 kg

• 5 kg

• 6 kg

60 kg of an alloy A is mixed with 100 kg of alloy B. If alloy A has lead and tin in the ratio 3 : 2 and alloy B has tin and copper in the ratio 1 : 4, the amount of tin in the new alloy is

• 53 kg

• 44 kg

• 80 kg

• 24 kg

A and B are two alloys of gold and copper prepared by mixing metals in the ratio 7 : 2 and 7 : 11 respectively. If equal quantities of the alloys are melted to form a third alloy C, the ratio of gold and copper in C wil be

• 5 : 7

• 5 : 9

• 7 : 5

• 9 : 5