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- Question
- The average height of 30 girls out of a class of 40 is 160 cms and that of the remaining girls is 156 cms. the average height of the whole class is?
Options- A. 11.8
- B. 25
- C. 29.5
- D. 30
- Correct Answer
- 30
ExplanationAverage height of the whole class = sum of height of 40 girls / 40
= (30 x 160 + 10 x 156) / 40
= 159 cms. - 1. The average score of a cricketer for 10 matches is 43.9 runs. If the average for the first six matches is 53 , the average for the last four matches is?
Options- A. 17.15
- B. 29.75
- C. 30.25
- D. 31 Discuss
- 2. The average of 50 number is 38 .if two numbers 45 and 55 are discarded , the average of the remaining number is?
Options- A. 36.5
- B. 37.0
- C. 37.5
- D. 37.52 Discuss
- 3. The average of 8 number 21. if each of the number is multiplied by 8,the new set of number is?
Options- A. 8
- B. 21
- C. 29
- D. 168 Discuss
- 4. What is the average of first 79 natural numbers?
Options- A. 79
- B. 39
- C. 40
- D. 39.5 Discuss
- 5. The average age of a group of 10 friends is 15 yr. If one friend leaves the group, the average becomes 16 yr. Find the age of the friend who left the group.
Options- A. 5 yr
- B. 4 yr
- C. 6 yr
- D. None of these Discuss
- 6. If a, b, c, d, e are five consecutive odd number , their average is?
Options- A. 5 (a + 4)
- B. abcd/5
- C. 5 (a + b + c + d + e)
- D. None of these Discuss
- 7. Out of three numbers, the first is twice the second and is half of the third. If the average of three number is 56, the three number in order are?
Options- A. 48, 96, 24
- B. 48, 24, 96
- C. 96, 24, 48
- D. 96, 48, 24 Discuss
- 8. The average of first nine multiples of 3 is?
Options- A. 12.0
- B. 12.5
- C. 15.0
- D. 18.5 Discuss
- 9. The average of five results is 46 and that of the first four is 45. the fifth result is?
Options- A. 51
- B. 50
- C. 49.5
- D. 49 Discuss
- 10. The average of 30 results is 20 and the average of other 20 results is 30 . what is the average of all the results?
Options- A. 24
- B. 25
- C. 48
- D. 50 Discuss
Average problems
Search Results
Correct Answer: 30.25
Explanation:
Let the average for last 4 matches be y.
Sum of score for 10 matches = sum of score for first 6 matches + sum of score of last 4 matches.
So 53 x 6 + 4y = 10 x 43.9
? 4x= 439-318
?4x= 121
? x= 30.25
Correct Answer: 37.5
Explanation:
Sum of 50 member = (50 x 38 )
= 1900
Sum of 48 member = [1900- (45 + 55 ) ]
= 1800
? Required Average = 1800/48
= 225/6
= 37.5
Correct Answer: 168
Explanation:
Average will increase by 8 times.
So average of new members = (21 x 8 ) = 168
Correct Answer: 40
Explanation:
Average of first n natural numbers = ( n + 1 ) / 2
= ( 79 + 1 ) / 2
= 40
Correct Answer: 6 yr
Explanation:
Age of friend left = Previous average of the age - Number of persons present x Increase in average age
= 15 - ( 10-1 ) x ( 16-15 )
= 15- 9 x 1
= 15 - 9 = 6yr
Correct Answer: None of these
Explanation:
Since a, b, c, d, e are 5 consecutive numbers so
b = a + 2.
c = a + 4.
d = a + 6.
e = a + 8.
Average = (a + b + c + d + e)/ 5
= [a + (a + 2 ) + (a +4 ) + (a+6 )+ (a+8)] / 5
= (5a+20) / 5
= a + 4
Correct Answer: 48, 24, 96
Explanation:
Let second number = x
So, first number = 2x and third number= 4x
? ( x + 2x + 4x ) / 3 = 56
? 7x = 168
? x = 24
So the numbers are 48,24, 96,
Correct Answer: 15.0
Explanation:
Average = ( 3 + 6 + 9 + 12 + 15 + 18 + 21 + 24 + 27 ) / 9
= 3(1+2+3+4+5+6+7+8+9)/9
= ( 45 / 3 )
= 15
Correct Answer: 49
Explanation:
Fifth result = sum of all five result - sum of first four result.
= 5 x 46 - 4 x 45
= 230 -180
=50
Correct Answer: 24
Explanation:
Sum of 50 result = sum of 30 result + sum of 20 result.
= 30 x 20 + 20 x 30
= 1200
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