It’s a shame bednobs hasn’t been back to let us know how useful our answers were. We were asked to show how to work out the percentage increase and the to provide the answer. I think most of the answers have done just that. We were not actually asked to provide an explanation of the methodology and I think criticism of the answers provided is a little unfair. So perhaps bednobs can tell us whether the answers provided so far suffice, or whether we were expected to provide something like this:
To find the percentage increase of something you firstly need to find the increase itself. Let’s say your numbers represent the price of an article in £££s. So the increase in your example is the difference between £144 and £115. Your article, originally valued at £115, has therefore increased by £29 (£144 minus £115).
“Percentage” means “for each hundred.” You know that your article has increased by 29 for each 115. To express this as a percentage, you need to calculate how many this is for each hundred. To do this, first of all, find out how much this is for every one. You do this by dividing your 29 increase by 115 (its base value). This works out as 0.2522. That is the increase for every pound of the base price. To calculate how much this is for every hundred pounds you multiply that number by 100. To do this, move the decimal point two places to the right, so the answer is 25.22%.
You can show this calculation arithmetically as (144-115)/115 x 100. On a calculator you would key in 144 minus 115; divide that answer by 115 and multiply that answer by 100.