reater than 3 tens 6 ones" probably means greater than 36, so maybe it's 37, 38, 39, and so on, up to 51. "It has more than 6 ones" probably means that it's got 7 or more in the ones place. so 40, 41, up to 46, and 50 and 51 can't be it. So we're left with 37, 38, 39, 47, 48, or 49 as possibilities for what Ava picked.