8/9 + (−5/ 6) divided by 1/6

4 times

Step-by-step explanation:

1 quart is equivalent to 32 fluid ounces.

If each eruption consumes 8 fluid ounces of vinegar. Assuming that the amount of vinegar required per eruption is constant, the number of times Tanvi can make her volcano erupt is:

Tanvi can make her volcano erupt 4 times  with 1 quart of vinegar.