Question

If the arithmetic mean of x, x + 3, x + 6, x + 9, and x + 12 is 10, the x =
(a)1
(b)2
(c)6
(d)4

Answer 1

SOLUTION :

The correct option is (d) : 4

Given : Mean = 10 , observations are : x, x + 3, x + 6 , x + 9 and x + 12 .

Total number of observations = 5  

Sum of observations = : (x + x + 3 + x + 6 + x + 9 + x + 12  = 5x + 30  

MEAN = Sum of the values of all the observations / Total number of observations

Mean = (5x + 30) / 5

10 = (5x + 30) / 5

10 × 5 = (5x + 30)  

50 = 5x + 30

5x = 50 - 30  

5x = 20  

x = 20/5 = 4  

x = 4  

Hence, the value of x is 4 .

HOPE THIS ANSWER WILL HELP YOU…….

Answer 2

If x+y=6,y+z=7,z+x=9, what is the average arithmetic of x, y and z?

Answer

45

: If x+y=6, y+z=7 and z+x=9, what is the average of x, y and z?

X+Y=6——————(1)X+Y=6——————(1)

Y+Z=7——————(2)Y+Z=7——————(2)

Z+X=9——————(3)Z+X=9——————(3)

Adding equation (1), (2) & (3) we get:

2(X+Y+Z)=22==>X+Y+Z=112(X+Y+Z)=22==>X+Y+Z=11

Average of X, Y and Z is (X+Y+Z)/3(X+Y+Z)/3

=11/3=11/3

So Average is3.67

..........Hope it helps............

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