The ratio of boys to girls is 3:2. If there are 30 students how many are girls?

Explanation: Total ratio parts = 3+2 = 5. Girls = (2/5)×30 = 12. Ratio and proportion problems are extensively tested. They require dividing quantities according to ratios and appear in problems about mixtures alloys speed partnership and map scales. Always identify the correct ratio part for the quantity being sought.