20m to 21m what is the percentage change

 The correct answer is:  " 5% increase " .

Step-by-step explanation:

Note:  The particular "percentage change" is a "percent increase" ; since we are going from "20" to "21" which is an "increased value of "1" .

Note the formula for "percent increase" ; as follows:

Percent increase = [(new value - original value)/original value] * 100 ;

So;  let us "plug in" our known values; to solve for the "percentage change"    

                 →  [i.e. "percent increase" (in this case)] :

 Percent increase  =  [(21 - 20)/20] * 100 ;

                                =  [1/20] * 100 ;

                                = [100/20] ;

                                = 5.

The correct answer is:  " 5 % increase" .

Hope this helps!

  Best wishes to you!

could

step-by-step explanation:

u send me a picture of ur work

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)