Hi, this comes down to the distributions. Since we know that we have six things in 8 spots, we know that either two things appear twice or one thing appears three times. Because of the rules about repetitions we know that two of them appear twice. That means that if there are two Js, they would have to go 1/5 or 2/7. Since we know that there must at least be one J before an H, we know that if there is only one J it must not be last, but we also know that if there are 2 Js they also can't be last.
