Math, asked by anmol3322, 1 year ago

the mean of five numbers is 7 After adding one more number the mean still remains 7 what is the new number


anmol3322: but this is not
niya25: wait a second I will edit
anmol3322: ok
niya25: you reported my answer
niya25: I was about to send u pic
niya25: let it be take help of others
anmol3322: no
anmol3322: ok bye

Answers

Answered by niya25
10
Mean =X = 27

No of observations = 7

 Sum of observations =  = 27 x 7 = 189

Let the included number be x

New Mean X' = 28

New number of observations = 8

New sum of observations =   28 x 8

                                              = 224 which is equal to  189+x

                                                     Thus x= 224-189 = 35   


niya25: is it ok
niya25: say me fast
anmol3322: but this is not answer
Answered by shashankavsthi
25
Let the numbers be a,b,c,d,e
 \frac{a + b + c + d + e}{5}  = 7 \\  \:  \: a + b + c + d + e = 35
let new number is x

 \frac{a + b + c + d + e + x}{6} =  7 \\  \: a + b + c + d + e + x = 42 \\ 35 + x = 42 \\ x = 7
new number is 7
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