Question

(18) The average of A and B is 25, B and C is 28, and
C and A is 21. Then the average of A, B and C
a. 23.66
b. 24.66
c. 25.66
d. 26.66​

Answer 1

Step-by-step explanation:

Given, A + B = 50

B + C = 56

C + A = 42

Adding these three, 2(A + B + C) = 148

A + B + C = 74

Average of A,B,C = 74/3

= 24.66

HOPE THIS HELPS YOU

Answer 2

Given:

The average of two numbers A and B is 25, B and C is 28 and, C and A is 21.

To Find:

The average of A, B and, C is?

Solution:

1. Let X1, X2, X3, .., Xn be n terms. The average of the n terms is given by the formula,

=> Average = (X1+X2+...+Xn)/n

2. The average of A and B is 25,

=> (A+B)/2 = 25,

=> A + B = 50. ( Assume as equation 1 ).

3. The average of B and C is 28,

=> (B+C)/2 = 28,

=> B + C = 56. ( Assume as equation 2 ).

4. The average of C and A is 21.

=> (A+C)/2 = 21,

=> A + C = 42. ( Assume as eqaution 3 ).

5. The average of A, B and C is ( A + B + C )/3.

=> Add equations 1, 2, and 3.

=> A + B + B + C + C + A = 50 + 56 + 42,

=> 2(A+B+C) = 148,

=> (A+B+C) = 74.

6. Average of A, B, and C is (A+B+C)/3,

=> Average = (A+B+C)/3 = (74)/3 = 24.66.

=> Average of A, B, and C is 24.66

Therefore, the average of A, B, and C is 24.66, Option B is the correct answer.