Question

If the mean of five observations x+1,x+3,x+5,2x+2,3x+3 is 14,find the mean of first three observations.

Answer 1

Heya !!!

Obsetvations are X + 1 , X + 3 , X + 5 , 2X +2 and 3X +3.

mean = Sum of obsetvations/Number of obsetvations.

14 = X + 1 + X + 3 + X + 5 + 2X + 2 + 3X / 5

14 = 7X + 14/5

8X + 14 = 14 × 5

8X +14 = 70

8X = 70-14

8X = 56

X = 56/8 = 7

Therefore,

First three observations = X + 1 , X + 3 , X +5 = 7 +1 , 7 + 3 , 7 +5

=> 8 , 10 , 12.

HOPE IT WILL HELP YOU...... :-)

Answer 2

Hi,

Here is your answer,

Given,

 The 5 observations :-  x + 1 , x + 3 , x +5, 2x +2 ,3x +3.
We know that,

Mean = Sum of observations/Number of observations. { FORMULA }

14 → x +1 + x+3 + x+5 + 2x+2 + 3x     /    5 { Now we are diving the whole equation by 5 as the number of observations are 5 }
→ 14 = 7x+ 14/5                                           { Here we are adding all the 5 observations }

                                            1x + 1x + 1x + 2x + 3x = 8x→ 8x + 14 = 14×5              

→ 8x +14 = 70        { + 14 with go to right hand side it will become -14 }

→ 8x = 70-14
→ 8x = 56
→ x = 56/8 

→ x = 7 

Now, Given
 We need to find the mean of first three observations → x + 1 , x + 3 , x +5
 
{we know the value of x = 7 so substitute the value of x in the first 3 observations}

 →  7 +1,7 + 3,7 +5 
→   8,10,12 ( ANSWER )


Hope it helps you !