Well if there are 85 questions and 20% of them are correct, basically 20% means 20/100 which when reduced is equivalent to 1/5. so then you would take 85 and multiply it by 1/5 to get 17. He got 17 questions correct
I showed you two different ways to get the same answer one with a fraction and one with a decimal. I think doing percentages as decimals is easier but thats just me.
Well, ratios are basically fractions. There are 12 boys, so the ratio is 12/25. Since 25 - 12 is 13, there are thirteen girls, so the ratio of girls to student is 13/25.
