The first answer is 39.47% decrease.
The second answer is 96.19% decrease.
Step-by-step explanation
For the first answer:
The number of accidents per 100,000 aircraft miles in 1960 was 0.38. In 1970 it was 0.23.
To find the percent increase or decrease, we first find the amount of increase or decrease:
0.38-0.23 = 0.15.
We now divide this by the first amount, 0.38:
0.15/0.38 = 0.3947 = 39.47%
Since it went from 0.38 to 0.23, this is a decrease.
For the second answer:
The value in 1950 was 3.15 and the value in 1975 was 0.12.
We first find the amount of increase or decrease:
3.15-0.12 = 3.03
We now divide this by the first number, 3.15:
3.03/3.15 = 0.9619 = 96.19%
Since it went from 3.15 to 0.12, this is a decrease.