First of all, you must convert 3/8 and 1/6 into similar denominators. You can do this by doing 3x6 and 8x6 for the first fraction and 1x8 and 6x8 for the second fraction.
Once you have done this, you get 18/48 on clothes and 8/48 on entertainment.
18/48 + 8/48 = 26/48 and so 48 - 26 = 22 so 22/48 was spent on other items. 22/48 simplified is equal to 11/24 and since that cannot be simplified anymore, your answer is 11/24 of her allowance was spent on other items.