13.) In 1990, a radio costs $25. Now,
the radio costs $5. What is the
percent of change?

Step-by-step explanation:

             80% of 25 = 5

because 10% of 25 = 2.5

and then       10 x 8 = 80

so                2.5 x 8 = 20

                  25 - 20 = 5

therefore, the percentage change is 80%

GIVE BRAINLIEST

hope this helped,

-cheesetoasty

you already gave the answer

step-by-step explanation:

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)