A discount string 5/2/1 means the following:
1) Apply 5% discount to the original price.
2) Apply 2% discount to the result of step 1).
3) Apply 1% discount to the result of step 2).
We have then that the result will be given by:
625 * (0.95) * (0.98) * (0.99) = 576.05625 $
Then, the price of each skateboard is:
(576.05625) /20=28.8028125 $
Answer:
The net price of the skateboards was:
28.8028125 $