There are 6 coins of value 10 and 4 coins of value 5 (thus, a total of 10 coins). A credit card is allowed to give only one bitcoin at a time. When anyone swipes the credit card, the card picks out a bitcoin out of its pool at random and pays. In total, Jane's card pays 2 bitcoins, one by one.
A vending machine will only accept Jane's payment if the second coin payed is of value 10.
What is the probability that Jane's payment will not be accepted?
Note: Once a bitcoin has been picked to be payed, no new bitcoins replace it in the credit card.