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Multiple choice maths average arithmetic mean of ap introduction to averages means

The  arithmatic mean of $4,6,8$ is

  1. $4$
  2. $6$
  3. $8$
  4. $4.5$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\Rightarrow$  First adding numbers $4,\, 6$ and $8$ = $4+6+8=18$

$\Rightarrow$   We have number of terms 3
$\Rightarrow$   $Arithemetic\, mean=\dfrac{S}{N}=\dfrac{18}{3}=6$

Multiple choice maths average arithmetic mean of ap introduction to averages means

Find AM of divisors of $100$.

  1. $24$
  2. $25.5$
  3. $24.11$
  4. $21.9$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Divisors of 100 are:

$1, 2, 4, 5, 10, 20, 25, 50, 100$
$\therefore n=9$
$\therefore S=1+2+4+5+10+20+25+50+100=217$
$\therefore A.M.=\dfrac{S}{n}=\dfrac{217}{9}=24.11$

Multiple choice maths average arithmetic mean of ap introduction to averages means

The  Sum of three numbers in AP is $75$, and product of extremities is $609$. The numbrs and AM of 1st two numbers is 

  1. $\{21,25,29\}$, AM $= 23$
  2. $\{13,17,21\}$, AM $= 22$
  3. $\{21,25,29\}$, AM $= 25$
  4. $\{21,22,29\}$, AM $= 23$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the numbers in A.P.  be (a-d), a, (a+d)

$\therefore (a-d)+a+(a+d)=75$
$\Rightarrow a=25$
Also, $(a-d)(a+d)=609$
$\Rightarrow a^{2}-d^{2}=609$
$\Rightarrow 25^{2}-d^{2}=609$
$\therefore d=\pm4$
The numbers are {21,25,29} or {29,25,21}
According to option, we take {21,25,29}
A.M. of 1st two numbers $=\dfrac{21+25}{2}=23$

Multiple choice maths average arithmetic mean of ap introduction to averages means

If the Arithmetic mean of $8, 6, 4, x, 3, 6, 0$ is $4$; then the value of $x =$

  1. $7$
  2. $6$
  3. $1$
  4. $4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Arithmetic mean $= \cfrac{\text{sum of all observations}}{\text{no. of observations}}$

$\Rightarrow 4=\cfrac { 8+6+4+x+3+6+0 }{ 7 } \ \Rightarrow 28=27+x\ \Rightarrow x=1$

Multiple choice maths average arithmetic mean of ap introduction to averages means

State the following statement is True or False
Arithmetic mean of first five natural numbers is $3$.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

First five natural numbers are $1 ,2 , 3 ,4, 5$

arithmetic mean = $\dfrac { sum\quad of\quad numbers }{ count\quad of\quad numbers } $
$ = \dfrac{1 + 2 + 3 + 4  + 5 }{ 5} $
$=\dfrac { 15 }{ 5 } =3$
Arithmetic mean of first five natural number is 3.
Hence the given statement is true.