1. Here are my hints. 10% of the drink is cordial and that you have 350mL of the drink at the start. First question what is 10% of 350mL, or you can go if 100 stands for 350 then what is 10 using the fact that percent is per a hundred. Then if we want that to be 8% only how much water do we need so that instead of being 10% it is only 8%?

2. We have one litre of milk here and from the composition we need to find what is 5% of one litre which is cream because our emphasis is on the cream. Now the next part of the question is that how much skimmed milk is needed so that the 5% of one litre is 4% ask yourself in the new sample what is a quarter of the cream amount and multiply by 100.

3. Start this question you need to see what this question is asking us to do. Now time to get into it. the cost of a car is reduced by 5% and then increased by 10% what is this telling us. Well if we reduce something by 5% we have 95% leftover and then if you increase something by 10% it is simply just 95% + 9.5% = 104.5%. One can also express this idea using fractions.

4. The easiest one to complete because you simply have to do these steps, start off with the fact that 80% of the water can be treated as a whole, now my question is what is one quarter of 80%. Once this step is answered ask yourself what is three quarters of that which can simply be done by multiplying by 3. Last step 80% - (...) = Percentage of water in the concentrated juice.

5. This is an interesting take because there is actually a very clever way that we can do this question. You see here that you have a 20% increase and then a 20% decrease right. Well guess what it happens twice so the way how I would approach such a question is to use decimals because they provide that info very clearly. Well you see

Find that and then numtiply by 100 to convert from decimals to percentages and then round it to the nearest percent and then the question is done.

Please note decimal comes from deci which is simply divided by 10 and then percent is simply per 100 as in per + century.