Part A: To calculate the total amount of water Tanya buys in milliliters, we need to calculate the sum of the water in the 300 milliliter bottles and the 1.5-liter bottles.
The number of 300 milliliter bottles is 5, and each bottle holds 300 milliliters. So, the total water from the 300 milliliter bottles is:
5 bottles * 300 milliliters/bottle = 1500 milliliters
The number of 1.5-liter bottles is 7, and each bottle holds 1.5 liters, which is equivalent to 1500 milliliters. So, the total water from the 1.5-liter bottles is:
7 bottles * 1500 milliliters/bottle = 10500 milliliters
To find the total amount of water in milliliters, we add the amounts from the two types of bottles:
1500 milliliters + 10500 milliliters = 12000 milliliters
Therefore, Tanya buys 12,000 milliliters of water.
Part B: To calculate the total amount of water Tanya buys in liters, we divide the total amount of water in milliliters by 1000 (since there are 1000 milliliters in a liter).
12000 milliliters / 1000 = 12 liters
Therefore, Tanya buys 12 liters of water.