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- Question
- The average age of 4 member of family is 20 yr. If youngest member is 4 yr. old, What was the average age of family at the time of the birth of youngest member?
Options- A. 27 yr
- B. 231/3 yr
- C. 211/3 yr
- D. 22 yr
- Correct Answer
- 211/3 yr
ExplanationTotal age of all members of the family (at present) = 20 x 4 = 80
4yr ago, total age of all members = 80 - ( 4 x 4) = 80- 16 = 64 yr.
As 4 yr ago, there were only 3 members in the family
? Average age of the family at the time of the birth of the youngest member
= 64/3
= 211/3 yr - 1. A class is divided into two sections A and B. Passing average of 20 students of section A is 80% and passing average of 30 students of sections B is 70%. What is the passing average of both the sections?
Options- A. 72%
- B. 74%
- C. 75%
- D. 77% Discuss
- 2. The average markes obtained by 120 students in an examination is 30. if the aveage marks of passed students is 40 and that of the failed students is 10. what is the 25% of the number of students who passed the examination?
Options- A. 30
- B. 20
- C. 40
- D. 15 Discuss
- 3. In a certain examination, the average marks of an examinee is 64 per paper. if he had obtained 18 more marks for his Mathematics paper and 4 more marks for his English paper, his average per paper would have been 66. How many papers were there in the examination?
Options- A. 11
- B. 13
- C. 9
- D. 15 Discuss
- 4. Nine friends have dinner in a hostel. Eight of them spent ? 12 each on their meals and the ninth spent ? 16 more than the average expenditure of all the nine. Find out the total money spent by them?
Options- A. ? 126
- B. ? 135
- C. ? 111
- D. ? 141 Discuss
- 5. The average age of three boys is 15 yr. If the ratio of their ages is 3 : 5 : 7, What is the age of the oldest boy?
Options- A. 7 yr
- B. 14 yr
- C. 20 yr
- D. 21 yr Discuss
- 6. 3 yr ago, the average age of a family of 5 members was 17 yr. Even after the birth of a child, the aveage is same today. Find out the age of child.
Options- A. 1 yr
- B. 3 yr
- C. 21/2
- D. 2 yr Discuss
- 7. A person bought some oranges worth ? 36 from each of the five markets at ? 1, ? 1.50, ? 1.80, ? 2 and ? 2.25 per orange, respectively. What is the average price of an orange?
Options- A. ? 1.91
- B. ? 2.00
- C. ? 1.58
- D. ? 1.80 Discuss
- 8. Average of a, b and c is 11; average of c, d and e is 17; average of e and f is 22 and average of e and c is 17. Find out the average of a, b, c, d, e and f?
Options- A. 152/3
- B. 181/2
- C. 211/3
- D. 161/2 Discuss
- 9. The average age of 54 girls in a class was calculated as 14 yr. It was later relized that the actual age of one of the girls in the class was 10.5 yr but it was calculated as 13 yr. What is the actual averge age (round off) of the the girls in the class? (Find the approximate answer.)
Options- A. 10.50 yr.
- B. 12.50 yr
- C. 12 yr
- D. 14 yr Discuss
- 10. The average age of a man and his two twin sons born on the same day is 30 yr. The ratio of the ages of father and one son is 5 : 2, What is the father's age?
Options- A. 50 yr
- B. 30 yr
- C. 45 yr
- D. 20 yr Discuss
Average problems
Search Results
Correct Answer: 74%
Explanation:
Here n1 = 20, n2 = 30, a1 = 80%, a2 = 70%
? Total average = (n1a1 + n2a2) / (n1 + n2)
= (20 x 80 + 30 x 70) / (20 + 30)
= (1600 + 2100) / 50
= 74%
Correct Answer: 20
Explanation:
Let number of passed students = N
Total marks = 120 x 30
According to the question,
40N + (120 - N) x 10 = 120 x 30
? 3600 = 40N + 1200 - 10N
? 30N = 2400
? N = 2400/30 = 80
? 25% of 80 = 80/4 = 20
Correct Answer: 11
Explanation:
Let the number of papers = x.
According to the question,
64x + 18 + 4 = 66x
? 2x = 22
? x = 22/2 = 11
Correct Answer: ? 126
Explanation:
Let average expenditure of 9 persons = x.
According to the question,
12 x 8 + (x + 16) = 9x
? 8x = 112
? x = 112/8 = 14
? Total money spent = 9x = 9 x 14 = ? 126
Correct Answer: 21 yr
Explanation:
Total age of all three boys
= 3 x 15 = 45 yr
Ratio of ages = 3 : 5 : 7
? Age of the oldest boy
= [7/(3 + 5 + 7)] x 45 = (7/15) x 45 = 21 yr
Correct Answer: 2 yr
Explanation:
3 yr ago, total age of 5 members of the family = 17 x 5 = 85 yr
Present age of all the members of the family = 85 + 3 x 5 = 100 yr
Let the age of the child = N yr
Present avrage age of family = (100 + N) / 6
[At present total number of members = 5 + 1 = 6]
17 = 100N / 6
? 102 = 100 + N
? N = 2 yr
Correct Answer: ? 1.58
Explanation:
Number of oranges bought by the person
= 36/1 + 36/1.50 + 36/1.80 + 36/2 + 36/2.25
= 36 + 24 + 20 + 18 + 16
= 114
Total expenditure = 36 x 5 = ? 180
Thus, average price of each orange
= ? 180/114
= ? 1.58
Correct Answer: 152/3
Explanation:
According to the question,
a + b + c = 11 x 3 = 33 ......(i)
c + d + e = 17 x 3 = 51 ...........(ii)
e + f = 22 x 2 = 44 ........... (iii)
e + c = 17 x 2 = 34 ..........(iv)
From Eqs. (ii) and (iv), we get
34 + d = 51
or d = 17 ....(v)
Now, by adding Eqs. (i), (iii) and (v), we get
a + b + c + d + e + f = 33 + 44 + 17 = 94
? Average of a, b, c, d, e and f = 94/6
= 47 / 3
= 152/3
Correct Answer: 14 yr
Explanation:
Total actual age of 54 girls = (54 x 14) - 13 + 10 .5
= 753.5 yr
? Require average age = 753.5/54
= 13.95 yr
= 14 yr(approx).
Correct Answer: 50 yr
Explanation:
According to the question,
Average age of man and his twin sons = 30
? Total age = 30 x 3 = 90 yr.
According to the question,
Ratio of father and one son = 5 : 2
? Ratio of father and both the sons = 5 : 2 : 2
(As sons are born on the same day.)
? 5k + 2k + 2k = 90 or 9k = 90
? k = 10
? Age of father = 5 x 10 = 50 yr.
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