Average
- A cricketer whose bowling average is 12.4 runs per wicket, takes 5 wickets for 26 runs and thereby decreases his average by 0.4. The number of wickets taken by him till the last match was
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Let required number of wickets = n
According to question,
⇒ 12.4 × n + 26 = (n + 5) (12.4 – 0.4)
⇒ 12.4 × n + 26 = (n + 5) × 12
⇒ 12.4n + 26 = 12n + 60
⇒ 12.4n – 12n = 60 – 26
⇒ 0.4n = 34Correct Option: D
Let required number of wickets = n
According to question,
⇒ 12.4 × n + 26 = (n + 5) (12.4 – 0.4)
⇒ 12.4 × n + 26 = (n + 5) × 12
⇒ 12.4n + 26 = 12n + 60
⇒ 12.4n – 12n = 60 – 26
⇒ 0.4n = 34
⇒ n = 34 ÷ 0.4∴ n = 340 = 85 4
- The average of 9 observations was found to be 35. Later on, it was detected that an observation 81 was misread as 18. The correct average of the observations is :
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Given that , The average of 9 observations = 35
Later on, it was detected that an observation 81 was misread as 18 .
Correct sum of 9 observations = 9 × 35 – 18 + 81
Correct sum of 9 observations = 315 + 63 = 378Correct Option: B
Given that , The average of 9 observations = 35
Later on, it was detected that an observation 81 was misread as 18 .
Correct sum of 9 observations = 9 × 35 – 18 + 81
Correct sum of 9 observations = 315 + 63 = 378
∴ Required correct average = 378 ÷ 9 = 42
- The average of runs of a cricket player of 10 innings was 32. How many runs must he make in his next inning so as to increase his average of runs by 4 ?
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Let the batsman make p runs.
Total runs in 10 innings = 10 × 32 = 320∴ 320 + p = 32 + 4 11
⇒ 320 + p = 36 × 11
⇒ p = 396 – 320 = 76
Second method to solve this question with the help of given formula :
Here, T = 32, N = 11, t = 4
Correct Option: A
Let the batsman make p runs.
Total runs in 10 innings = 10 × 32 = 320∴ 320 + p = 32 + 4 11
⇒ 320 + p = 36 × 11
⇒ p = 396 – 320 = 76
Second method to solve this question with the help of given formula :
Here, T = 32, N = 11, t = 4
Required Run = T + Nt [Here N is taken as (n + 1)]
Required Run = 32 + 11 × 4
Required Run = 32 + 44 = 76
- A cricket player after playing 10 tests scored 100 runs in the 11th test. As a result, the average of his runs is increased by 5. The present average of runs is
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Here , A cricket player after playing 10 tests scored in the 11th match = 100 runs
If the average in 10 tests be n , then
According to question ,
⇒ n × 10 + 100 = (n + 5) × 11
⇒ 11n – 10n = 100 – 55Correct Option: C
Here , A cricket player after playing 10 tests scored in the 11th match = 100 runs
If the average in 10 tests be n , then
According to question ,
⇒ n × 10 + 100 = (n + 5) × 11
⇒ 11n – 10n = 100 – 55
⇒ n = 45
∴ Required average = 50
- A student, by mistake, wrote 64 in place of 46 as a number at the time of finding the average of 10 given numbers and got the average as 50. The correct average of the numbers is :
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Here , Average of 10 given numbers = 50
A student, by mistake, wrote 64 in place of 46 , then
Correct sum of numbers = 10 × 50 – 64 + 46
Correct sum of numbers = 500 – 18 = 482Correct Option: A
Here , Average of 10 given numbers = 50
A student, by mistake, wrote 64 in place of 46 , then
Correct sum of numbers = 10 × 50 – 64 + 46
Correct sum of numbers = 500 – 18 = 482
∴ Correct average = 482 ÷ 10 = 48.2