Explanation:
you would take 45 and divide it by 3 which would give you what one witch = 15
take 21 divide it by 3 which gives you one wand =7
take the brooms and divide it 12 by 3 one broom = 3
then take the wand(15) and multiply is but the wand (7) =105
take 105 and add the broom too it(4) = 109
so the answer is 109