flash-aquarium

gistfile1.txt

<USER>
### 2. Aquarium

In the aquarium, there are octopuses with eight arms and starfish with five arms.

**How many starfish are there in the aquarium if the total number of arms of all the animals living in it is 41?**

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Here's how to solve this problem:

**Let:**

*  'x' be the number of octopuses
*  'y' be the number of starfish

**Set up the equation:**

The total number of arms is 41.  Octopuses have 8 arms, and starfish have 5. So the equation is:

8x + 5y = 41

**Solve for possible values:**

We need to find whole number solutions for x and y since we can't have fractions of animals.

* **Try x = 0:** 5y = 41.  y = 8.2 (Not a whole number, so this doesn't work)
* **Try x = 1:** 8 + 5y = 41. 5y = 33. y = 6.6 (Not a whole number)
* **Try x = 2:** 16 + 5y = 41. 5y = 25. y = 5 (This works!)
* **Try x = 3:** 24 + 5y = 41. 5y = 17. y = 3.4 (Not a whole number)
* **Try x = 4:** 32 + 5y = 41. 5y = 9. y = 1.8 (Not a whole number)
* **Try x = 5:** 40 + 5y = 41. 5y = 1. y = 0.2 (Not a whole number)

**Solution:**

The only whole number solution is x = 2 and y = 5.

**Answer:**

There are 5 starfish in the aquarium.