Answer: 7
Each tickmark is 1/8 of a gallon. Start at 0 and count out 7 ticks to the right to land on the largest amount measured, which is 7/8. This is 7 times larger than 1/8 which is at the opposite end at the smallest measurement.
largest = 7*(smallest)
7/8 = 7*(1/8)
7/8 = 7/8