Question

the average of five numbers is 27. if one number is excluded,the average become 25.what is the excluded no.
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Answer 1

Let a,b,c,d and e be the 5 numbers,

Given that,

27 = (a+b+c+d+e)/ 5

a+b+c+d+e = 135 .......(1)

Now let "e" is being excluded and average becomes 25

25 = (a+b+c+d)/4
a+b+c+d = 100 .........(2)

Using (2) in (1)

100+e = 135
e = 35 .....(Answer)

Note: - Average of n numbers is equal to summation of n numbers divided by n.

Answer 2

$\underline\bold{\huge{SOLUTIONS\: :}}$

Let the Total sum be Of Five No's be "X"

Now, According to the question

Average of Five no's. is 27

So,

$\frac{x}{5} = 27$

$= > x = 5 \times 27$

$= > x = 135$

$\underline\bold{So, total\: sum \:of\: five\: no's.is \:135\: :}$

Again given that one no.is excluded

So, total no's now is 4

Now,new Sum of nos.be Y(say)

$\frac{y}{4} = 25$

$= > y = 4 \times 25$

$= > y = 100$

$\underline\bold{So, now \:new\: total sum \:of \:4\: numbers\: is \:100\: :}$

Now Subtract" y" from "x" to got the number.

=135-100

=35

$\red{\huge{So, the \:no. \:is \:35}}$