Answer:
If Kristen were to make 4 batches, and each batch requires 2 cups of flour, how many cups of flour would she need? To solve this question, we would just multiply 4 by 2, which gives us a final product of 8.
Similarly, in this question, if one batch requires 1 3/4 cups of flour and Kristen wants to bake 3 1/2 batches, she would need 1 3/4 x 3 1/2 cups of flour.
1 3/4 can be rewritten as an improper fraction- 7/4.
3 1/2 can also be rewritten as an improper fraction- 7/2.
Multiplying 7/4 and 7/2, we obtain a final product of 49/8, or 6 1/8.
This means, Kristen will need 6 1/8 cups of flour to make 3 1/2 batches, and her belief that she needs 3 3/8 cups of flour is wrong, as she needs a lot more than that.
Hope this helps!