A boy uses a single fixed pulley to lift a load of 50 kgf to some height. Another boy uses a single movable pulley to lift the same load to the same height. The ratio of the two effort is:

1. 1:2
2. 2:1
3. 1:1
4. none of these

How many strands are supporting the load in case of block and tackle system of 5 pulleys?  

1. 4
2. 5
3. 6
4. 7

For greater efficiency of block and tackle pulley system:

1. The lower block should be of negligible weight.
2. The upper block should be of negligible weight.
3. The number of pulleys should be minimum.
4. The weight of the rope should be equal to the weight of the pulleys.