The average age of 12 students is 20 years. If the age of one more student is included, the average decreases by 1. What is the age of the new student?
A. 5 years B. 7 years C. 9 years D. 11 years
Correct Answer: B
Explanation
To find the age of the new student, follow these steps:
1. Calculate the Total Age of the 12 Students: - Average age of 12 students = 20 years - Total age of 12 students = Average age × Number of students - Total age = 20 × 12 = 240 years
2. Calculate the Total Age with the New Student: - After including the new student, the average age decreases to 19 years. - Total number of students becomes 13. - Total age of 13 students = Average age × Number of students - Total age = 19 × 13 = 247 years
3. Find the Age of the New Student: - The age of the new student = Total age of 13 students - Total age of 12 students - Age of the new student = 247 - 240 = 7 years
