10? Im not sure though my friend just told me it was 10
Let’s look at the permutations of the letters “ABC.” We can write the letters in any of the following ways:
ABC
ACB
BAC
BCA
CBA
CAB
Since there are 3 choices for the first spot, two for the next and 1 for the last we end up with (3)(2)(1) = 6 permutations. Using the symbolism of permutations we have:

. Note that the first 3 should also be small and low like the second one but I couldn’t get that to look right.
Now let’s see how this changes if the letters are AAB. Since the two As are identical, we end up with fewer permutations.
AAB
ABA
BAA
To make the point a bit better let’s think of one A are regular and one as bold
A.
ABA and AB
A look different now because we used bold for one of the As but if we don’t do this we see that these are actual the same. If they represented a word they would be the same exact word.
So in this case the formula would be

. We use 2! In the denominator because there are 2 repeating letters. If there were three we would use 3!
Hopefully, this is enough to let you see that the answer is A. The number of permutations is limited by the number of items that are identical.
To solve this problem, all we have to do is to thoroughly
analyze the situation step by step.
First let us work on the remaining 10 gallons of water in
the tank. We are given that 2 / 3 of the water initially in the tank leaked
out. Therefore this means that we are left with 1 / 3 the original amount of
water which is 10 gallons, hence:
(1 / 3) Vi = 10 gallons
where Vi is the initial volume of water inside the tank,
calculating for Vi:
Vi = 3 (10 gallons)
Vi = 30 gallons
We are also given that this initial volume of water is
just 3 / 4 of the total capacity of the tank, therefore:
(3 / 4) Vc = Vi
where Vc is the volume capacity of the tank, calculating
for Vc:
Vc = 4 Vi / 3
Vc = 4 (30 gallons) / 3
Vc = 40 gallons
Answer:
<span>Capacity of the fish tank is 40 gallons</span>
Ok so area is length times width. A square has the same sides all around, which is called a quadrilateral. So you would plug in 40 for length and width. 40x40= 1,600 cm^2 <———— is your answer.
Hope this helped :)