Average problems
- 1. 12 boys decided to constribute Rs. 750 each to an Orphange. Suddenly few of them boys dropped out and consequently the rest had to pay Rs. 150 more. Then the number of boys who dropped out?
Options- A. 4
- B. 6
- C. 2
- D. 3 Also asked in: AIEEE, Bank Exams, CAT, GATE, Analyst, Bank Clerk, Bank PO, Database Administrator
Correct Answer: 2
Explanation:
Total money decided to contribute = 750 x 12 = 9000
Let 'b' boys dropped
The rest paid 150/- more
=> (12 - b) x 900 = 9000
=> b = 2
Hence, the number of boys who dropped out is 2.
- 2. The average of six numbers is 3.95. The average of two of them is 3.4, while the average of the other two is 3.85. What is the average of the remaining two numbers ?
Options- A. 3.6
- B. 4.6
- C. 6.5
- D. 7.3 Discuss
Correct Answer: 4.6
Explanation:
Sum of the remaining two numbers = (3.95 * 6) - [(3.4 * 2) + (3.85 * 2)]
= 23.70 - (6.8 + 7.7) = 23.70 - 14.5 = 9.20.
Required average = (9.2 / 2) = 4.6.
- 3. In an NGO the daily average wages of 20 illiterate employees is decreased from Rs.25 to Rs.10, thus the average salary of all the literate and illiterate employees is decreased Rs.10 per day. The No. of educated employees working in the NGO is :
Options- A. 15
- B. 20
- C. 10
- D. Data Insufficient Discuss
Correct Answer: 10
Explanation:
Total employees =
Hence number of educated employees = 30-20 = 10
- 4. A man covers a journey from Meerut to Delhi by a car at an average speed of 40 km/hr. He returns back by scooter with an average speed 24 km/hr. Find his average speed during the whole journey?
Options- A. 32 kmph
- B. 27 kmph
- C. 30 kmph
- D. 31 kmph Discuss
Correct Answer: 30 kmph
Explanation:
Since equal distances are covered at 40 kmph and 24 kmph, we can apply the formula 2xy/(x+y) Average speed= (2×40×24)/(40+24) = 30 kmph
- 5. The average score of boys in an examination in a school is 81 and that of the girls is 83 and the average score of the school is 81.8. Then what will be ratio between the number of girls to the number of boys, in the examination?
Options- A. 3:2
- B. 2:3
- C. 4:3
- D. 3:4 Also asked in: AIEEE, Bank Exams, CAT, GATE, Analyst, Bank Clerk, Bank PO
Correct Answer: 2:3
Explanation:
Let the number of boys = b
Let the number of girls = g
From the given data,
81b + 83g = 81.8(b + g)
81.8b - 81b = 83g - 81.8g
0.8b = 1.2g
b/g = 1.2/0.8 = 12/8 = 3/2
=> g : b = 2 : 3
Hence, ratio between the number of girls to the number of boys = 2 : 3.
- 6. A student's average marks in five subjects is 82. If the average marks of first two subject is 86.5 and the average marks of last two subjects is 84. Find the marks of third subject?
Options- A. 69
- B. 67
- C. 71
- D. 73 Also asked in: AIEEE, Bank Exams, CAT, Analyst, Bank Clerk, Bank PO
Correct Answer: 69
Explanation:
The total marks of all 5 subjects = 82 x 5 = 410
Total marks of 1st two subjects = 86.5 x 2 = 173
Total marks of last two subjects = 84 x 2 = 168
Now, marks in 3rd subject = 410 - (173 + 168) = 410 - 341 = 69.
- 7. A batsman in his 17th innings makes a score of 85 and their by increasing his average by 3. What is his average after the 17th innings ?
Options- A. 34
- B. 36
- C. 35
- D. 37 Also asked in: AIEEE, Bank Exams, CAT, GATE, Bank Clerk, Bank PO
Correct Answer: 37
Explanation:
16x + 85 = 17(x + 3)
x = 34 + 3 = 37
- 8. Five boxes of bananas sell for Rs. 30. how many boxes can you buy for Rs.9?
Options- A. 2
- B. 1.5
- C. 1.25
- D. 2.5 Also asked in: AIEEE, Bank Exams, CAT, GATE, Analyst, Bank Clerk, Bank PO, Database Administrator
Correct Answer: 1.5
Explanation:
Given Five boxes of bananas sell for Rs. 30.
=> 1 Box of Bananas for = 30/5 = Rs. 6
Then, for Rs. 9
=> 9/6 = 3/2 = 1.5
Hence, for Rs. 9, 1.5 box of bananas can buy.
- 9. Ian has 14 boxes of paper and divides them evenly between 4 coworkers. How many whole boxes did each coworker get?
Options- A. 2
- B. 2.5
- C. 3
- D. 3.5 Also asked in: AIEEE, Bank Exams, CAT, GATE, Analyst, Bank Clerk, Bank PO
Correct Answer: 3
Explanation:
Given number of boxes = 14
Number of workers = 4
Now, number of whole boxes per worker = 14/4 = 3.5
Hence, number of whole boxes per each coworker = 3
- 10. The average price of 10 books is Rs. 12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what ia the pice of each of these two books ?
Options- A. 16,12
- B. 10,16
- C. 23,9
- D. 8,7 Discuss
Correct Answer: 10,16
Explanation:
Total pice of the two books = Rs. [(12 x 10) - (11.75 x 8)]
= Rs. (120 - 94) = Rs. 26.
let the price of one book be Rs. x
Then, the price of other book = Rs. (x + 60% of x) = Rs.(x+(3/5)x) = Rs. (8/5)x
So, x+(8/5)x =26 <=> x =10
The prices of the two books are Rs. 10 and Rs. 16
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