Im confused when it comes to increasing/decreaseing a value by a ratio

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Im currently doing GCSE maths and the current topic is ratios. Im comfortable sharing a value between ratios but im confused by questions like

Increase £30 in the ratio of 5:2

My materials arent very clear and its frustrating me, could someone please explain the method for calculating this type of answer?

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I think what they are thinking is:

(new number of pounds):(old number of pounds)::5:2

Or in words: the ratio of the result to the starting value should be the same as 5 to 2.

So if our result is X, we have $$\frac X{30} = \frac52$$

Multiply both sides by 30 to find X.