STEP 1:
Tally up the total number of batches.
= 3 batches + 4 batches
= 7 batches
STEP 2:
Multiply the total number of batches by the amount of butter used in one batch (which is 1/4 cup).
= 7 batches * 1/4 cup per batch
= 7 * 1/4
= (7*1)/4
= 7/4
= 1 3/4 cup of butter
Beth used 1 3/4 cup of butter to make a total of 7 batches of cookies.
Hope this helps! :)