Calculating the Number of Fish in a School

This problem asks us to find the total number of fish in a school given the total weight of the school and the weight of each individual fish. We are given the total weight in kilograms (kg) and the weight of each fish in grams (g). To find the number of fish, we need to make sure both weights are in the same unit.

Unit Conversion: Kilograms to Grams

The total weight of the school of fish is 3 kg. The weight of each fish is 150 g. We need to convert the total weight from kilograms to grams. We know that 1 kilogram is equal to 1000 grams. So, to convert kilograms to grams, we multiply the weight in kilograms by 1000.

Total weight in grams = Total weight in kilograms $\times$ Conversion factor

Total weight in grams = $3 \text{ kg} \times 1000 \text{ g/kg}$

Total weight in grams = $3000 \text{ g}$

Now we have the total weight of the school of fish as 3000 g, and the weight of each fish as 150 g.

Finding the Number of Fish

To find the number of fish in the school, we can divide the total weight of the school by the weight of a single fish.

Number of fish = $\frac{\text{Total weight of the school}}{\text{Weight of each fish}}$

Number of fish = $\frac{3000 \text{ g}}{150 \text{ g}}$

Calculation:

To simplify the division $\frac{3000}{150}$, we can first cancel out a zero from the numerator and the denominator:

$\frac{3000}{150} = \frac{300}{15}$

Now, we can perform the division. 300 divided by 15. We know that $15 \times 2 = 30$. So, $15 \times 20 = 300$.

$\frac{300}{15} = 20$

So, the number of fish in the school is 20.

The calculation confirms that if the total weight is 3000g and each fish is 150g, there are 20 fish.