10 संख्याओ का माध्य 30 है । बाद में ज्ञात हुआ की त्रुटी के कारण 15,23 को 51,32 अंकित किया गया । सही माध्य ज्ञात करे ?

Options

A. 25.5
B. 32
C. 30
D. 34.5

Answer

A

Explanation

According to the question
mean of 10 numbers is =30
`therefore` sum of 10 numbers is =300
It was observed that numbers 15,23 are wrongly taken as 51,32 Difference =(51+32)-(15+23)=83-38=45 (more)
`therefore` Actual sum of 10 numbers =300-45=255
`therefore` Actual avg of 10 numbers `=255/10=25.5`
Alternate
Sum of correct numbers =15+23=38
Sum of incorrect numbers =51+32=83
Difference =83-38=45
The difference of 45 effect the 10 numbers =`45/10=4.5`
wrong average =30
correct average =30-4.5=25.5