Question

21. A quantity of food would last a

family of 5 for 21 days. How long
would the same quantity last a
family of 7 if thev all eat at the same
rate?​

Answer 1

15 days

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.

⇒
`(x)/(21)` =
`(1)/((7)/(5) )`

⇒
`(x)/(21)` =
`(5)/(7)`

⇒ x =
`(21 * 5)/(7)`

x = 15

∴ It would take a family of 7 15 days to finish a quantity of food.

Hope this helps!!!

Answer 2

15 days

Explanation:

5 x 21 = 105

105/7 = 15