In order to obtain a standard deviation of 0, all members of the data set should be equal.
This means that each of the 100 members in the data set is equal to 50 (the mean value).
Answer:
The smallest observation in the set is 50.
0.3*42 this gives you a 30% discount
3/10*42 this gives you a 30% discount
0.03*42 this gives you a 3% discount
3 *4.2 This is not a discount
