Create a data set that has five values. the mean of the data set should be 34.

Start with 34,34,34,34,34
minus 5 from 1 number and add 5 to another
29,34,34,34,39
minus 2 from a number and add 2 to another
29,32,36,34,39
minus 10 from a number and add 10 to another
19,32,36,44,39
repeat as many times as needed

basically
if the 5 numbers are x,y,z,t,a then
(x+y+z+t+a)/5=34
times 5 both sides
x+y+z+t+a=170
just find 5 numbers that add to 170

100,20,20,20,5,5 is another one

The discount is 8.70 . you dont tell us the percent of tax added so there is no way to find out, unless i'm not seeing anything. without tax its 37.70