Well

translates to

so
log5(x/2)=5 means 5^5=x/2, so 3125=x/2, so 6250=x
The average rate of change between two input values is the total change of the function values (output values) divided by the change in the input values.
Victoria's method is linear because the number of minutes increase by an equal number (15) every month.
Workings in the attachments below. The green line is the function that has been set up for Victoria. The lines that form a curved looking graph belong to the function that was set up for Zach.
X = log (base b) y
The base of the log becomes the base of the exponent.
The x and y switch.
b^x = y
Answer:
(1/2)% = 0.5% =0.5/100 = 0.005
=> Option E is correct.
Hope this helps!
:)