Katrina drinks 0.5 gallons of water per day. Which expression shows how to find the number of cups of water she drinks in a week?

There are 16 cups in a gallon.

A. [tex]\(\frac{0.5 \text{ gallons}}{1 \text{ day}} \times \frac{16 \text{ cups}}{1 \text{ gallon}} \times \frac{1 \text{ week}}{7 \text{ days}}\)[/tex]

B. [tex]\(\frac{0.5 \text{ gallons}}{1 \text{ day}} \times \frac{1 \text{ gallon}}{16 \text{ cups}} \times \frac{7 \text{ days}}{1 \text{ week}}\)[/tex]

C. [tex]\(\frac{0.5 \text{ gallons}}{1 \text{ day}} \times \frac{1 \text{ gallon}}{16 \text{ cups}} \times \frac{1 \text{ week}}{7 \text{ days}}\)[/tex]

D. [tex]\(\frac{0.5 \text{ gallons}}{1 \text{ day}} \times \frac{16 \text{ cups}}{1 \text{ gallon}} \times \frac{7 \text{ days}}{1 \text{ week}}\)[/tex]



Answer :

To find the number of cups of water Katrina drinks in a week, we need to perform a unit conversion and multiplication over the number of days in a week.

Here’s a step-by-step breakdown:

1. Gallons to Cups Conversion:
Katrina drinks 0.5 gallons of water per day. Since there are 16 cups in 1 gallon, we need to convert gallons to cups.

2. Daily Consumption in Cups:
We calculate the daily consumption in cups by multiplying the number of gallons consumed per day by the number of cups in a gallon:
[tex]\[ 0.5 \text{ gallons/day} \times 16 \text{ cups/gallon} \][/tex]
This simplifies to:
[tex]\[ 8 \text{ cups/day} \][/tex]

3. Weekly Consumption:
We then multiply the daily consumption in cups by the number of days in a week. There are 7 days in a week, so:
[tex]\[ 8 \text{ cups/day} \times 7 \text{ days/week} \][/tex]
This simplifies to:
[tex]\[ 56 \text{ cups/week} \][/tex]

Given the expressions provided:
- [tex]\(\frac{0.5 \text { gallons }}{1 \text { day }} \times \frac{16 \text { cups }}{1 \text { gallon }} \times \frac{1 \text { week }}{7 \text { days }}\)[/tex]
- [tex]\(\frac{0.5 \text { gallons }}{1 \text { day }} \times \frac{1 \text { gallon }}{16 \text { cups }} \times \frac{7 \text { days }}{1 \text { week }}\)[/tex]
- [tex]\(\frac{0.5 \text { gallons }}{1 \text { day }} \times \frac{1 \text { gallon }}{16 \text { cups }} \times \frac{1 \text { week }}{7 \text { days }}\)[/tex]
- [tex]\(\frac{0.5 \text { gallons }}{1 \text { day }} \times \frac{16 \text { cups }}{1 \text { gallon }} \times \frac{7 \text { days }}{1 \text { week }}\)[/tex]

The correct expression that represents the steps we took is:
[tex]\[ \frac{0.5 \text { gallons }}{1 \text { day }} \times \frac{16 \text { cups }}{1 \text { gallon }} \times \frac{7 \text { days }}{1 \text { week }} \][/tex]

This expression correctly converts gallons to cups (by multiplying by [tex]\(\frac{16 \text{ cups}}{1 \text{ gallon}}\)[/tex]) and then multiplies by the number of days in a week.

Therefore, the correct expression is the last one:
[tex]\[ \frac{0.5 \text { gallons }}{1 \text { day }} \times \frac{16 \text { cups }}{1 \text { gallon }} \times \frac{7 \text { days }}{1 \text { week }} \][/tex]