8gallons
Step-by-step explanation:
If Joe drinks 10 liters of water every week, then;
10liters = 1 week
After 3weeks;
x litres =3 weeks
Divide both expressions
10/x = 1/3
x = 3*10
x = 30litres
This means he consumes 30litres in 3 weeks
If there are approximately 19 liters in 5 gallons, the;
19litres = 5gallons
To determine the number of gallons consumed in 3 weeks;
30litres = y
Divide both expressions
19/30 = 5/y
Cross multiply
19 * y = 30*5
19y = 150
y = 150/19
y = 7.89
y ≈ 8 (to nearest whole number)
Hence Joe drinks 8gallons of water in 3weeks