Question

if a+b+c+d=24, and the average if a and b is 4 what is the average of c and d?

Answer 1

$a + b + c + d = 24 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: ...(i)$



$\textbf{Given, Average of a and b is 4 }$


$average \: = \frac{a + b}{2} \\ \\ \\ = > 4 = \frac{a + b}{2} \\ \\ \\ = > 8 = a + b \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: ... (ii)$



$\text{Putting the value of a + b from ( i ) to ( ii ) , }$




Hence,


=> a + b + c + d = 24

=> 8 + c + d = 24

=> c + d = 24 - 8

$=> c + d = 16 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: ...(iii)$







Then,



$average \: \: of \: \: c \: \: and \: \: \: d = \frac{c + d}{2}$

$\textbf{ Putting the value from ( iii ) , }$



$= > average \: = \frac{16}{2} \\ \\ = > average \: = 8$







Average of c and d = 8

Answer 2

Hey there !

Solution:

Average of two numbers = Sum of two Numbers / 2

Given that,

• a + b + c + d = 24

• ( a + b ) / 2 = 4

=> a + b = 2 × 4

=> a + b = 8 => Equation 1

Substituting this in the given equation we get,

=> 8 + c + d = 24

=> c + d = 24 - 8

=> c + d = 16

Dividing by 2 on both sides we get,

=> ( c + d ) / 2 = 16 / 2

=> ( c + d ) / 2 = 8

Hence the average of c and d is 8.

Hope my answer helped !