Which set of numbers is arranged in descending order?

a 7.2 x 10^-30, 7 x 10^-30, 7.6 x 10^-25, 7.2 x 10^-25
b 7.6 x 10^-25, 7.2 x 10^-25, 7.2 x 10^-30, 7 x 10^-30
c 7.6 x 10^-25, 7.2 x 10^-30, 7.2 x 10^-25, 7 x 10^-30
d 7 x 10^-30, 7.2 x 10^-25, 7.2 x 10^30, 7.6 x 10^-25

The set of numbers that is arranged in descending order is:

c 7.6 x 10^-25, 7.2 x 10^-30, 7.2 x 10^-25, 7 x 10^-30

The set of numbers arranged in descending order is:

c) 7.6 x 10^-25, 7.2 x 10^-30, 7.2 x 10^-25, 7 x 10^-30

To determine which set of numbers is arranged in descending order, we need to compare the numbers in each set.

In set a, the numbers are:
- 7.2 x 10^-30
- 7 x 10^-30
- 7.6 x 10^-25
- 7.2 x 10^-25

If we compare the exponents, we can see that 10^-30 is smaller than 10^-25, so the first two numbers are in the correct order. However, when we compare the last two numbers, 7.6 x 10^-25 and 7.2 x 10^-25, we can see that 7.2 x 10^-25 is smaller than 7.6 x 10^-25. Therefore, set a is not arranged in descending order.

In set b, the numbers are:
- 7.6 x 10^-25
- 7.2 x 10^-25
- 7.2 x 10^-30
- 7 x 10^-30

If we compare the exponents, we can see that 10^-25 is larger than 10^-30, so the first two numbers are in the correct order. When we compare the last two numbers, 7.2 x 10^-30 and 7 x 10^-30, we can see that 7 x 10^-30 is smaller than 7.2 x 10^-30. Therefore, set b is not arranged in descending order.

In set c, the numbers are:
- 7.6 x 10^-25
- 7.2 x 10^-30
- 7.2 x 10^-25
- 7 x 10^-30

If we compare the exponents, we can see that 10^-25 is larger than 10^-30, so the first and third numbers are in the correct order. However, when we compare the second and fourth numbers, 7.2 x 10^-30 and 7 x 10^-30, we can see that 7.2 x 10^-30 is larger than 7 x 10^-30. Therefore, set c is not arranged in descending order.

In set d, the numbers are:
- 7 x 10^-30
- 7.2 x 10^-25
- 7.2 x 10^30
- 7.6 x 10^-25

If we compare the exponents, we can see that 10^-30 is smaller than 10^-25, so the first two numbers are in the correct order. When we compare the last two numbers, 7.2 x 10^-25 and 7.6 x 10^-25, we can see that 7.6 x 10^-25 is larger than 7.2 x 10^-25. Therefore, set d is not arranged in descending order.

Based on our comparisons, none of the given sets are arranged in descending order.