A small pool is being drained. There are 1500 gallons of water remaining in the pool after 5 minutes and 1000 gallons after 10 minutes. How much water was in the pool BEFORE it started draining.

3 answers

Let's call the initial amount of water in the pool "x".

We know that after 5 minutes, there are 1500 gallons of water remaining. This means that in the first 5 minutes, (x - 1500) gallons of water were drained.

Similarly, after 10 minutes, there are 1000 gallons of water remaining. This means that in the next 5 minutes (from 5 to 10 minutes), another (1500 - 1000) = 500 gallons were drained.

So in total, (x - 1500) + 500 = (x - 1000) gallons of water were drained in 10 minutes.

Simplifying this equation, we get:

x - 1000 = (x - 1500) + 500

x - 1000 = x - 1000

Solving for x, we get:

x = 2000

So there were originally 2000 gallons of water in the pool before it started draining.
The first five terms of an arithmetic sequence are 29, 25.5, 22, 18.5, and 15. Which function, f(n), could be used to describe the nth term of the sequence?
Let's first find the common difference, d, between consecutive terms in this arithmetic sequence:

d = 25.5 - 29 = -3.5
d = 22 - 25.5 = -3.5
d = 18.5 - 22 = -3.5
d = 15 - 18.5 = -3.5

We see that the common difference is -3.5 for this arithmetic sequence. Now we can use this to find the general formula for the nth term using the formula:

a_n = a_1 + (n - 1)d

where a_n is the nth term, a_1 is the first term, n is the term number, and d is the common difference.

Using the given first term, a_1 = 29, and the common difference, d = -3.5, we get:

a_n = 29 + (n - 1)(-3.5)

Simplifying and rearranging, we get:

a_n = 32.5 - 3.5n

Therefore, the function f(n) that could be used to describe the nth term of the sequence is:

f(n) = 32.5 - 3.5n