15 संख्याओं का औसत 20 है, उनमें से पहली 6 संख्याओं का औसत 19 है और अंतिम
7 संख्याओं का औसत 18 है। यदि सातवी संख्या आठवीं संख्या का 2/3 हो, तो उन दोनों
संख्याओं को बतलाइये।।
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Step-by-step explanation:
mean of 15 observation is 20 then sum of all these numbers is equal to 15×20 = 300
And mean of 6 observation is 19 , then sum of these numbers = 19 × 6 = 109
mean of last 7 observation = 18 ,then sum of these numbers = 18×7= 126
so, 7th and 8th observation 's sum is
300-126+109
= 300-235= 65
let 7th observation is x and 8th is y.
And z = x/3
then 65/5 =z
z=13
then x= 13×3=39
and y = 2/3 × x
y = 2/3 × 39
y = 2×13= 25
so, 7th and 8th observation are 26 and 39 respectively.
Sorry bhot large karke samjhaya
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