The ratio of the number of boys and girls in a school of 720 students is 7 : 5. How many more girls should be admitted to make the ratio 1 : 1?

1. 90

2. 120

3. 220

4. 240

Two numbers are in the ratio 7 : 11. If 7 is added to each of the numbers, the ratio becomes 2 : 3. The smaller number is:

1. 39

2. 49

3. 66

4. 77

If p, q, and r are in continued proportion, then :

1. p : q = p : r

2. q : r = p² : q²

3. p : q² = r : p²

4. p : r = p² : q²

The ratio of milk to water in 80 litres of a mixture is 7 : 3. The quantity of water (in litres) to be added to it to make the ratio 2 : 1 is :

1. 4

2. 5

3. 6

4. 8