The receip calls for 1 3/4 cups of brown sugar. if she makes 2 1/2 batches of cookies, how much brown sugar does she need

1 and 3/4 cups = 4/4 + 3/4 = 7/4 cups This equals 1 batch. If we want 2.5 batches, then we multiply by 2.5 2.5 x 7/4  = x 4.375 cups = x You can also add the cups one batch and then a half batch at a time. 7/4 + 7/4 + (7/4*1/2) = x multiply the first two (7/4) by 2/2 so there is a common denominator of 8 Then you have 14/8 + 14/8 + 7/8 = 35/8 = 4.375 cups

It will take him 5 days