Question

How much water do you add to make each concentration? 1% sugar syrup using 12 g sugar.

Its not 75g or 33g!!!

Answer 1

You want the 12g of sugar to be 1% of the whole solution.

So, say you add grams of water. The solution will be composed of 12 grams of sugar and grams of water, for a total of grams.

So, the ratio "sugar/total" will be

and we want this ratio to be 1%, i.e. 1/100:

Multiply both sides by 100 and to get

Subtract 12 from both sides:

So, a solution composed of 1188 grams of water and 12 grams of sugar will be 99% water and 1% sugar.

The next exercise is just the same: you can build and solve the following equation

(I used the fact that 75% is three quarters). You should find the solution x=33.

Explanation: