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The average height of 20 students of a c...

The average height of 20 students of a class is 105 cm. If ten more students of average height of 120 cm join the class, then the average height of the class is______

A

115 cm

B

117.5 cm

C

112.5 cm

D

110 cm

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we can follow these calculations: **Step 1: Calculate the total height of the first 20 students.** - The average height of the first 20 students is 105 cm. - Total height = Average height × Number of students - Total height of 20 students = 105 cm × 20 = 2100 cm. **Step 2: Calculate the total height of the 10 new students.** - The average height of the new 10 students is 120 cm. - Total height of 10 students = Average height × Number of students - Total height of 10 students = 120 cm × 10 = 1200 cm. **Step 3: Calculate the total height of all students in the class after the new students join.** - Total height of all students = Total height of first 20 students + Total height of 10 new students - Total height of all students = 2100 cm + 1200 cm = 3300 cm. **Step 4: Calculate the total number of students in the class.** - Total number of students = 20 (original) + 10 (new) = 30 students. **Step 5: Calculate the average height of the class.** - Average height = Total height of all students / Total number of students - Average height = 3300 cm / 30 = 110 cm. Thus, the average height of the class after the new students join is **110 cm**. ---
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