Question

Which set of numbers
is arranged in descending
order? (1 point)
,
,
,
7.6 × 10
−25
7.2 × 10
−30
7.2 × 10
−25
7 × 10
−30
,
,
,
7 × 10
−30
7.2 × 10
−25
7.2 × 10
−30
7.6 × 10
−25
,
,
,
7.2 × 10
−30
7 × 10
−30
7.6 × 10
−25
7.2 × 10
−25
,
,
,
7.6 × 10
−25
7.2 × 10
−25
7.2 × 10
−30
7 × 10

Answer 1

To determine which set of numbers is arranged in descending order, we need to compare their values based on their scientific notation.

In scientific notation, a number is expressed as \( a \times 10^b \), where \( a \) is a coefficient and \( b \) is the exponent. The value is primarily determined by the exponent \( b \); a larger exponent indicates a larger number when comparing numbers with the same base.

Let’s break down the options provided:

1. **Set 1**:
- \( 7.6 \times 10^{-25} \)
- \( 7.2 \times 10^{-30} \)
- \( 7.2 \times 10^{-25} \)
- \( 7 \times 10^{-30} \)

Value order: \( 7.6 \times 10^{-25} > 7.2 \times 10^{-25} > 7.2 \times 10^{-30} > 7 \times 10^{-30} \)

2. **Set 2**:
- \( 7 \times 10^{-30} \)
- \( 7.2 \times 10^{-25} \)
- \( 7.2 \times 10^{-30} \)
- \( 7.6 \times 10^{-25} \)

Value order: \( 7.6 \times 10^{-25} > 7.2 \times 10^{-25} > 7.2 \times 10^{-30} > 7 \times 10^{-30} \) (not in descending order)

3. **Set 3**:
- \( 7.2 \times 10^{-30} \)
- \( 7 \times 10^{-30} \)
- \( 7.6 \times 10^{-25} \)
- \( 7.2 \times 10^{-25} \)

Value order: \( 7.6 \times 10^{-25} > 7.2 \times 10^{-25} > 7.2 \times 10^{-30} > 7 \times 10^{-30} \) (not in descending order)

4. **Set 4**:
- \( 7.6 \times 10^{-25} \)
- \( 7.2 \times 10^{-25} \)
- \( 7.2 \times 10^{-30} \)
- \( 7 \times 10^{-30} \)

Value order: \( 7.6 \times 10^{-25} > 7.2 \times 10^{-25} > 7.2 \times 10^{-30} > 7 \times 10^{-30} \)

**Conclusion**:

The first and fourth sets are in descending order:
- **Set 1**: \( 7.6 \times 10^{-25}, 7.2 \times 10^{-25}, 7.2 \times 10^{-30}, 7 \times 10^{-30} \)
- **Set 4**: \( 7.6 \times 10^{-25}, 7.2 \times 10^{-25}, 7.2 \times 10^{-30}, 7 \times 10^{-30} \)

Either Set 1 or Set 4 is correct. If only one set should be chosen, then it is generally the first given set:

1. \( 7.6 \times 10^{-25}, 7.2 \times 10^{-25}, 7.2 \times 10^{-30}, 7 \times 10^{-30} \) (This is a valid answer as they are in descending order).