Janine is considering buying a water filter and a reusable water bottle rather than buying bottled water. Will doing so save her money?
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How much water does Janine drink in a day? She normally drinks 6 bottles a day, each 16.9 ounces.
How much does a bottle of water cost? She buys 24-packs of 16.9 ounce bottles for $3.69.
How much does a reusable water bottle cost? About $10.
How long does a reusable water bottle last? Basically forever (or until you lose it).
How much does a water filter cost? How much water will they filter?
A faucet-mounted filter costs about $28 and includes one filter cartridge. Refill filters cost about $33 for a 3-pack. The box says each filter will filter up to 100 gallons (378 liters)
A water filter pitcher costs about $22 and includes one filter cartridge. Refill filters cost about $20 for a 4-pack. The box says each filter lasts for 40 gallons or 2 months
An under-sink filter costs $130 and includes one filter cartridge. Refill filters cost about $60 each. The filter lasts for 500 gallons
Which choice is better?
Faucet Mounted Filter
The cheapest option saves her 277.91 a year but why what is the formula?
This is why I posted the question can anyone answer it?
To determine which choice is better, we need to calculate the cost of buying bottled water versus using a water filter and reusable water bottle.
First, let's calculate the cost of buying bottled water:
Janine drinks 6 bottles of water a day, and each bottle is 16.9 ounces. So, she consumes a total of 6 * 16.9 = 101.4 ounces of water per day.
Since a bottle of water is 16.9 ounces, Janine needs 101.4 / 16.9 = 6 bottles of water per day.
If Janine buys a 24-pack of 16.9 ounce bottles for $3.69, this means that she would need (6 bottles / 24 bottles) * $3.69 = $0.92 per day.
Now let's calculate the cost of using a water filter and reusable water bottle:
The cost of a reusable water bottle is about $10, and it lasts forever.
For the water filter, we need to consider the different options available:
1. Faucet-mounted filter:
The initial cost of a faucet-mounted filter is $28, and it includes one filter cartridge. The refill filters cost $33 for a 3-pack, and each filter cartridge can filter up to 100 gallons.
If each filter cartridge lasts for 100 gallons, Janine would need to replace it every (101.4 ounces * 365 days) / 128 ounces/gallon = 289.33 days. This means that Janine would need to buy 2 sets of 3-pack refill filters, which would cost 2 * $33 = $66.
Therefore, the total cost of using a faucet-mounted filter and reusable water bottle for a year would be $10 (reusable water bottle) + $28 (initial cost of filter) + $66 (refill filters) = $104.
2. Water filter pitcher:
The initial cost of a water filter pitcher is $22, and it includes one filter cartridge. The refill filters cost $20 for a 4-pack, and each filter cartridge lasts for 40 gallons or 2 months.
If each filter cartridge lasts for 40 gallons, Janine would need to replace it every (101.4 ounces * 365 days) / 640 ounces/gallon = 57.96 days. This means that Janine would need to buy 6 sets of 4-pack refill filters, which would cost 6 * $20 = $120.
Therefore, the total cost of using a water filter pitcher and reusable water bottle for a year would be $10 (reusable water bottle) + $22 (initial cost of filter) + $120 (refill filters) = $152.
3. Under-sink filter:
The initial cost of an under-sink filter is $130, and it includes one filter cartridge. The refill filters cost $60 each, and the filter lasts for 500 gallons.
If the filter lasts for 500 gallons, Janine would need to replace it every (101.4 ounces * 365 days) / 128 ounces/gallon = 289.33 days. This means that Janine would need to buy 1 set of refill filters, which would cost $60.
Therefore, the total cost of using an under-sink filter and reusable water bottle for a year would be $10 (reusable water bottle) + $130 (initial cost of filter) + $60 (refill filters) = $200.
Comparing the costs:
- Buying bottled water would cost $0.92 per day or $336.80 per year.
- Using a faucet-mounted filter would cost $104 per year.
- Using a water filter pitcher would cost $152 per year.
- Using an under-sink filter would cost $200 per year.
Based on these calculations, it is clear that using a water filter and reusable water bottle would save Janine money compared to buying bottled water. The faucet-mounted filter option offers the most cost savings, followed by the water filter pitcher and then the under-sink filter.
To determine whether buying a water filter and a reusable water bottle will save Janine money compared to buying bottled water, we need to calculate the cost of each option.
Option 1: Buying bottled water
Janine drinks 6 bottles of water per day, with each bottle containing 16.9 ounces. Let's convert this to gallons: 6 bottles * 16.9 oz/bottle = 101.4 oz/day. Since there are 128 ounces in a gallon, Janine drinks approximately 0.79 gallons of water per day.
A pack of 24 bottles costs $3.69, and each bottle contains 16.9 ounces. Therefore, the cost per gallon is calculated as follows: $3.69 / (24 bottles * 16.9 oz/bottle) = $0.0918 per ounce * 128 oz/gallon ≈ $11.76 per gallon.
Option 2: Buying a water filter and a reusable water bottle
The cost of a reusable water bottle is $10, and it lasts indefinitely.
Now, let's consider the cost of a water filter. Different types of filters have varying costs and lifespans.
- Faucet-mounted filter: The initial cost is $28, and a 3-pack of refill filters costs $33. Each filter can filter up to 100 gallons. The cost per gallon is calculated as follows: ($28 + $33) / 3 filters / 100 gallons = $0.20 per gallon.
- Water filter pitcher: The initial cost is $22, and a 4-pack of refill filters costs $20. Each filter lasts for 40 gallons or 2 months. Assuming Janine drinks 0.79 gallons per day, a filter will last approximately 50 days. The cost per gallon is calculated as follows: ($22 + $20) / 4 filters / 40 gallons = $0.33 per gallon.
- Under-sink filter: The initial cost is $130, and each refill filter costs $60. The filter lasts for 500 gallons. The cost per gallon is calculated as follows: ($130 + $60) / 500 gallons = $0.38 per gallon.
Comparing the costs per gallon:
- Bottled water: $11.76 per gallon
- Faucet-mounted filter: $0.20 per gallon
- Water filter pitcher: $0.33 per gallon
- Under-sink filter: $0.38 per gallon
Based on these calculations, purchasing a faucet-mounted filter would be the most cost-effective option for Janine, saving her money compared to buying bottled water. However, the specific choice depends on her preference, budget, and desired convenience.