Mathematics for IGCSE & O level - Ratio And Proportion (Section 4 - No. 45)
The ratio of boys to girls in a class is 3:4. If there are 28 students in the class, how many girls are there?
12
16
21
32
Explicació
Total ratio parts: 3+4=7. Proportion of girls: 4/7. Number of girls = (4/7) * 28 = 16