Author 
Topic 

sri340
Average Member
USA
18 Posts 
Posted  11/13/2008 : 07:41:13

Average age of A & B is 24 years and average of B, C & D is 22
years. The sum of the ages A, B, C & D is
a)90 years b) 96 years c)114 years d)data inadequate



Haven
Senior Member
USA
28 Posts 
Posted  11/13/2008 : 11:37:28

To solve this problem you must have an understanding of what an average is and know how to use the average formula.
To solve this problem:
The first step is to find the value of A or B. The problem tells you that the average of A + B equals 24; by using the average formula this means that A + B divided by 2 equals 24, or multiplying both sides by 2 gives you A + B equals 48. the average value of A or B equals 24.
The second step is to substitute 24 into the second average problem of (B) + C + D = 22; this means that 24 + C + D divided by 3 equals 22, or multiplying both sides by 3 gives 24 + C + D = 66. Subtracting 24 from each side now gives the following C + D = 42
The third step is to take the values of A + B which equals 48, and C + D which equals 42 and add them together; 48 + 42 = 90
I hope this explanation was of some help to you.



Ultraglide
Advanced Member
Canada
299 Posts 
Posted  11/13/2008 : 12:53:54

How do you know B is 24 when you substituted it into B+C+D? 


Haven
Senior Member
USA
28 Posts 
Posted  11/13/2008 : 18:04:02

I made an assumption based upon my understanding of the word "average" and the information given. If my assumption was incorrect, then I stand corrected and kindly give a better explanation.
Thanks 


Subhotosh Khan
Advanced Member
USA
9116 Posts 
Posted  11/13/2008 : 18:15:47

the correct response to the problem is  insufficient data. 


the_hill1962
Advanced Member
USA
1468 Posts 
Posted  11/14/2008 : 12:49:44

I was thinking that "insufficient data" is the correct response. The ONLY data given is two equations: 1. (A+B)/2 = 24 2. (B+C+D)/3 = 22 This means that [3(A+B) + 2(B+C+D)]/6 = 46. That is 3A+5B+5C+2D=276, nothing more.

Edited by  the_hill1962 on 11/14/2008 12:51:05 


Haven
Senior Member
USA
28 Posts 
Posted  11/14/2008 : 15:00:03

Thanks. 



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