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

Two numbers are in the ratio of 3 : 5. If 9 is subtracted from each, they are in the ratio of 12 : 23. The larger number is :

1. 40

2. 45

3. 55

4. 60

What number must be added to the terms of 3 : 5 to make the ratio 5 : 6 ?

1. 6

2. 7

3. 12

4. 13