If x, y, z are in continued proportion, then (y² + z²) : (x² + y²) is equal to :

1. z : x

2. x : z

3. x : y

4. (y + z) : (x + y)

In an alloy, the ratio of copper and zinc is 5 : 2. If 1.250 kg of zinc is mixed in 17 kg 500 g of alloy, then the ratio of copper and zinc in the alloy will be :

1. 1 : 2

2. 2 : 1

3. 2 : 3

4. 3 : 2