Medium
Fill in the blank: The ratio of boys to girls in a class is 4 : 5. If the class has 36 students in all, the number of girls is ______.
Explanation
Explanation
Step 1: Total parts in the ratio = 4 + 5 = 9 parts.
Step 2: These 9 parts stand for 36 students, so 1 part = 36 ÷ 9 = 4 students.
Step 3: Girls = 5 parts = 5 × 4 = 20.
Step 4: Check: boys = 4 × 4 = 16 and 16 + 20 = 36 ✓.
Answer: 20 girls.
PRO TIP
Re-check your working by substituting the answer back into the original question.