Question

The average age of A.B and C is 40 years. If the age of B is (9/10) of this average, what is the average
A and C together?​

Answer 1

Step-by-step explanation:

sum of age a+b+c=40×3 = 120

b =9/10 ×40 =36

sum of a and c =120-36 = 84

average a and c =84/2 =42

answer is 42

Answer 2

The average  A and C together is 42

Step-by-step explanation:

$Average = \frac{\text{Sum of all observations}}{\text{No. of observations}}$

We are given that The average age of A.B and C is 40 years.

So, 40 = \frac{\text{Sum of ages of A , B and C}}{3}

40 \times 3 = \text{Sum of ages of A , B and C}

120= \text{Sum of ages of A , B and C}

We are given that the age of B is (9/10) of this average

So, B's age = $\frac{9}{10}\times 40 = 36$

So, Sum of ages of A and C = 120-36 = 84

Average of age of A and C = $\frac{84}{2}=42$

Hence  the average  A and C together is 42

#Learn more:

Find the average of 40,50,60,70,80

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