Question:
12 fish were placed in two aquariums so that one of them had 2 times more fish than the other. How many fish are in each aquarium? Choose the correct answer: 12 and 6; 3 and 6; 8 and 4; 10 and 5. Prove that it is correct.
Answer:
Correct answer: 8 and 4
Step 1: Define variables
Let x be the number of fish in one aquarium.
Then 2x is the number of fish in the second aquarium (since there are 2 times more).
Step 2: Formulate the equation
The total number of fish in two aquariums is 12:
x + 2x = 12
Step 3: Solve the equation
Add x and 2x:
3x = 12
Divide both sides by 3:
x = 12 ÷ 3 = 4
Step 4: Find the number of fish in each aquarium
In the first aquarium: x = 4 fish
In the second aquarium: 2x = 2 × 4 = 8 fish
Step 5: Check the correctness of the answer
- Total number of fish: 4 + 8 = 12 ✓
- One aquarium has 2 times more: 8 ÷ 4 = 2 ✓
Answer checked and correct!
Why are other options incorrect?
- 12 and 6: 12 + 6 = 18 ≠ 12
- 3 and 6: 3 + 6 = 9 ≠ 12, and 6 ÷ 3 = 2, but the sum is not 12
- 10 and 5: 10 + 5 = 15 ≠ 12
