What measure word should I use when I have two nouns with different measure words?
In this case, a more correct way would be:


  你在动物园看了几只老虎和几匹马呀？


or 


  你在动物园看了多少只老虎，多少匹马？


In colloquial speech, it might be ok to say:


  你在动物园看了多少个老虎和马呀？


or


  你在动物园看了几个老虎和马呀？