Answer: 12$
Step-by-step explanation:
We need to round 79.45 to the nearest 10 dollars, which is 80.
We can then get 15% of it easily since its a whole number by adding 10% (8) and 5% (4) to get an estimate of around 12 dollars.
Answer:
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.