In a class of 50 boys and 30 girls, the average heights of the two groups of boys and girls are 150 cm and 140 cm respectively. The average height of the class isQuestion 18Answera.146.5b.146.25c.146d.146.75
Question
In a class of 50 boys and 30 girls, the average heights of the two groups of boys and girls are 150 cm and 140 cm respectively. The average height of the class isQuestion 18Answera.146.5b.146.25c.146d.146.75
Solution
To solve this problem, we need to find the total height of all the students and then divide it by the total number of students.
Step 1: Find the total height of the boys The average height of the boys is 150 cm. So, the total height of the boys is 150 cm * 50 = 7500 cm.
Step 2: Find the total height of the girls The average height of the girls is 140 cm. So, the total height of the girls is 140 cm * 30 = 4200 cm.
Step 3: Find the total height of all the students The total height of all the students is the sum of the total height of the boys and the total height of the girls. So, the total height of all the students is 7500 cm + 4200 cm = 11700 cm.
Step 4: Find the total number of students The total number of students is the sum of the number of boys and the number of girls. So, the total number of students is 50 + 30 = 80.
Step 5: Find the average height of the class The average height of the class is the total height of all the students divided by the total number of students. So, the average height of the class is 11700 cm / 80 = 146.25 cm.
So, the answer is b. 146.25.
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