**To x litres of an x% solution of acid, y litres of water is added to get (x –10)% solution of acid. If x > 20, then value of y is**

A] x^{2 }/100

B] 10x/(x-10)

C] 10x/(x+10)

D] 10x^{2 }/x-10

**A grocer purchased 2 kg. of rice at the rate of Rs.15 per kg. and 3 kg. of rice at the rate of Rs.13 per kg. At what price per kg. should he sell the mixture to earn profit on the cost price?**

A] Rs.28.00

B] Rs.20.00

C] Rs.18.40

D] Rs.17.40

**In 1 kg mixture of sand and iron, 20% is iron. How much sand should be addd, so that the proportion of iron becomes 5%?**

A] 3 kg

B] 4 kg

C] 5 kg

D] 6 kg

**In a mixture of milk and water the proportion of water by weight was 75%. If in the 60 gms mixture 15 gms, water was added, what would be the percentage of water in the new mixture?**

A] 75%

B] 88%

C] 90%

D] None

A and B are two alloys of gold and copper prepared by missing 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 will be:

A] 5: 7

B] 5: 9

C] 7: 5

D] 9:5