Question
The average age of a group of 9 teachers is 50 years.
When the principal retires, the average age of the remaining teachers drops to 45 years. Find the age of the principal.Solution
Let the age of the principal be ‘x’ years. So, x + (50 – 5) × 8 = 9 × 50 x + 45 × 8 = 450 x + 360 = 450 x = 450 – 360 x = 90 years So, age of the principal was 90 years.
The average age of a group of 12 students is 32 years. Two persons of age 40 years and 31 years, left the group and 2 persons of age 54 years and...
Sum of ages of 90 players is 1800 years. The average age of 40 of them is 16 years and the average age of another 30 of them is 14 years. Find the avera...
The average income of 'Pawan', 'Qureshi,' and 'Ranjan' is Rs. 'y', and their incomes are in the ratio of 5:3:4, respectively. 'Pa...
The average score of 'x' boys is (x + 5), and the average score of 30 girls is (3x - 10). If the combined average score of all students is 60, then find...
A batsman scores 87 runs in the 21st match of his career. His average runs per match increases by 2. What was his average before the 21st match.
The average weight of ‘x’ group members is 56 kg. The average weight of (x – 18) women is 55 kg, of (x – 20) children is 50 kg, and of (x – 22...
Average of nine consecutive numbers is 65. Find the sum of smallest and largest number.
The average weight of a family of 8 members is 85 kg. If the youngest member dies, the average weight of the family decreases by 1 kg. Find the weight o...
32 × 15 + 60% of 200 = ? + 120
In an examination the average marks of Rohit is 54. If he got 18 more marks in science and 22 more marks in maths then his average would have been 58. F...
