Answer:
The best estimation of the fraction of the batch that was left is 5/84
Step-by-step explanation:
Mr. Gallegos has:
A batch of muffins = 1
He gave 11/21 of the batch to his neighbors:
1 - 11/21 = 21/21 - 11/21 = 10/21
He ate 1/8 of the batch himself:
10/21 - 1/8 = 10/168
= 10/168 (dividing by 2)
= 5/84
The best estimation of the fraction of the batch that was left is 5/84
