something wrong with stroke

Question
Hello, I am 14 years old and have been competitively swimming for 8. I've been doing pretty well, but I am noticing that there are a couple things that might be wrong with my strokes:

Butterfly: I've noticed that my strokes are a lot longer and slower than other swimmer..is that ok or may that be a problem with not having enough arm strength? Also, whenever I do more than a 25, my stroke is ok the first 25, but it tends to slow down...is that normal? Should I do some more training on my upper body? How can I make my strokes go quicker? (I tend to rest a lot during the stroke, at the point where the arms come back around and are in a streamline like position, so that may be the case)

Backstroke: First of all, my start is not that great. And again, in backstroke, my coach says the tempo for my arms are too slow. Is this normal to have slow strokes or is it just lack of strength? Again, How can I get my tempo increase?

Breaststroke: My lower body is very powerful, but again, it's in my arms- my coach says I'm gliding enough, but I make too little arm motion. Should I try to strengthen my arms?

Thanks so much, and if you have any drills that might help any of these things, please include that! Thanks!

Answer
Laura--
It does sound like a little bit of a strength problem, but there is nothing wrong with a slow tempo as long as you are not going slower because of it.  If you are only swimming 50's yes you need a quicker turnover, but in longer distances a slow turnover can help save energy for the second half.  You do need to concentrate on picking up your tempo on the last half of your swims.  This you have to do by just concentrating on it.  One drill you can do is to work on taking more strokes than normal each lap, but still remember that during races make your stroke as efficient as possible.
To build strength in you arms, you need to do pull sets.  Use a kickboard or a pull-bouy between your thighs and work on just your arms.
Hope this helps,
George