How much water should we add to 35kg of sugar syrup to change it's concentration from 30% to 25%

Water = 1/5 of the volume of the syrup

Step-by-.step explanation:

Suppose we had  1000 cm^3 of syrup  and the new volume after adding water is x cm^3.  Now the amount of sugar stays the same so we have the equation 35 * 1000 =  25 * x

x = (30 * 1000) / 25 =  30,000 / 25

= 1200 cm^3

So we need to add 200 cm^2 of water .

In general terms,  we need to add water which equals 1/5 of the volume of the syrup,

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)