Answer:
15 days
Step-by-step explanation:
As the number of people in that family increases the time taken reduces, so the time is in inverse proportion to the number of people in that family.
Let the number of days taken by a family of 7 to finish a quantity of food be x.
⇒ [tex]\frac{x}{21}[/tex] = [tex]\frac{1}{\frac{7}{5} }[/tex]
⇒ [tex]\frac{x}{21}[/tex] = [tex]\frac{5}{7}[/tex]
⇒ x = [tex]\frac{21 * 5}{7}[/tex]
x = 15
∴ It would take a family of 7 15 days to finish a quantity of food.
Hope this helps!!!
