Answer: [tex]a_n= 1.25( a_{n-1} - 16)[/tex]
Step-by-step explanation:
Let initially the total quantity of the drink = [tex]a_{n-1}[/tex]
Then after 1 day the quantity of the drink = [tex]a_{n}[/tex]
Since, according to the question,
Each day, her brother drinks 16 ounces. Then at the end of each day Jill adds 25% of the remaining total back into the lemonade container.
That is, [tex]a_n= (a_{n-1}-16)+ 25% of (a_{n-1}-16)[\tex] =
[tex]a_n= (a_{n-1}-16)+ \frac{25}{100}\times (a_{n-1}-16)[/tex]
⇒ [tex]a_n= (a_{n-1}-16)+ 0.25\times (a_{n-1}-16)[/tex]
⇒ [tex]a_n= a_{n-1}-16+ 0.25 a_{n-1}-0.25\times 16[/tex]
⇒ [tex]a_n= 1.25 a_{n-1}-0.25\times 16-16[/tex]
⇒ [tex]a_n= 1.25 a_{n-1}-20[/tex]
⇒ [tex]a_n= 1.25( a_{n-1} - 16)[/tex] where [tex]a_1 = 64[/tex]
Which is the required recursive formula.
Thus, Option first correct.