Given that,
A supply of foods last for a week for 20 families.
It is required to find the time that would the supply last for 3 more families.
20 families = 1 week = 7 days
If 3 more families joined, total no of families are now 23.
It means that,
1 family= (20/7) days
Now,
23 family =
[tex]\dfrac{20}{7}\times 23=65.71\ \text{days}\\\\\approx 66\ \text{days}[/tex]
So, the supply will last for 66 days.
