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April 11th, 2018, 07:03 PM   #1
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Find the age of A 5 years hence.

The Present average age of 4 persons A, B , C and D is 37 years. A's age is equal to the average of B and C together and B's age is equal to the average age of A and C together. If the present age of C is 44 years. Find the age of A 5 years hence.

My try:

$\displaystyle A = \frac {B+C}{2}$

$\displaystyle B = \frac {C+D}{2}$

$\displaystyle \frac {\frac{\frac{C+D}{2} + C}{2} +\frac {C+D}{2} +C + D}{4}$

$\displaystyle \frac {\frac {44+D}{2} +44 + 3(44+D)}{2}$

$\displaystyle 4(44+D) + 88 = 37\times4$

I tried so much. But my approach is right or wrong? if wrong, please tell the correct procedure.

Last edited by Ganesh Ujwal; April 11th, 2018 at 07:15 PM.
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April 12th, 2018, 03:37 AM   #2
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If your opening paragraph is correct, you know that
(A + B + C + D)/4 = 37, A = (B + C)/2, B = (A + C)/2, and C = 44,
and the solution of those equations is (A, B, C, D) = (44, 44, 44, 16).
This means that A's age 5 years hence is 49.

If you intended that B's age equals the average age of C and D together, you know
(A + B + C + D)/4 = 37, A = (B + C)/2, B = (C + D)/2, and C = 44,
and the solution of those equations is (A, B, C, D) = (40, 36, 44, 28).
This would mean that A's age 5 years hence is 45.
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