Answer:
The n th of the given sequence is 
Step-by-step explanation:
<u>Step 1</u> :-
Given sequence is 20,14,8,2,.......this sequence in arithmetic progression but this sequence is decreasing sequence.
given first term is 20 and difference is
now the nth term of given sequence is
by using formula 


final answer:-

<u>verification</u>:-

put n=1 we get first term is 20
put n=2 we get second term is 14
put n=3 we get third term is 8
put n=4 we get fourth term is 2
so the n th term of sequence is

So first you need to find out how much one water bottle cost.
6/24= 0.25
Okay now you need to find how much it would cost for 10.
so you would times 10 by $0.25:
10*0.25= $2.50
So $2.50 would be you answer.
Hope that helps!!
Have a wonderful day!!