1.
The average age of class of 24 students is 24 years. The average increased by 1 when the teacher's age is also included. What is the teacher's age?
- A.45
- C.49
- B.47
- D.48
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
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2.
When the present age of the mother is added to the present age of the daughter, the sum is 40 years. What will be their total ages after 5 years?
- A.40 years
- C.35 years
- B.45 years
- D.50 years
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| Let the present age of mother be x |
| Daughter's age = 40 - x |
| After 5 years, mother's age = x + 5 |
| Daughter's age = 40 - x + 5 |
| Total age = x + 5 + 40 - x + 5 = 50 years |
3.
The average of class of 30 students is 21 years. When the teacher's age is included, the average increases by 1. What is teacher's age?
- A.50
- C.55
- B.51
- D.52
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
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4.
The average age of class of 20 students is 20 years. If the teacher's age is included the average increases by 1. What is the age of the teacher?
- A.40
- C.31
- B.41
- D.42
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
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5.
The sum of the ages of a father and his two sons who are twins is 48. Ten years hence, his age will be twice the sum of the son’s ages. Find the present age of one son.
- A.13 years
- C.8 years
- B.9 years
- D.3 years
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| Let the father’s age be x and the age of each son be y. |
| Then, x + 2y = 48 -------------(1) |
| 10 years hence, x + 10 = 2 (y + 10 + y + 10) |
| x +10 = 4y + 40 |
| 4y – x = -30 --------(2) |
| Solving (1) and (2) we get |
| (1) + (2) |
| 6y = 18 |
| y = 3 and x = 48 – 6 = 42 |
| Age of one son = 3 years |
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