Question

Mean of three number A,B,C is 55 and mean of four number A,B,C,D is 61.Find the value of D?​

Answer 1

Answer:

79

step by step explanation

a+b+c÷3=55

a+b+c=165

a+b+c+d÷4=61

165+d=244

d=79

Answer 2

Answer:

D = 79

Step-by-step explanation:

Given that-

Mean of A, B and C = 55

Mean of A, B, C, and D = 61

We know that-

$Mean \ of \ n \ numbers \ = \dfrac{Sum \ of \ n \ numbers}{n}$

So, $mean \ of \ A, B \ and \ C = \dfrac{A+B+C}{3}$

$55 = \dfrac{A+B+C}{3}$

A + B + C = 55×3

A + B+ C = 165

Similarly, $Mean \ of \ A, B, C \ and D = \dfrac{A+B+C+D}{4}$

$61 = \dfrac{A+B+C+D}{4}$

A + B + C + D = 61×4

A + B + C + D = 244

But A + B + C = 165

So, 165 + D = 244

D = 244 - 165

D = 79