The ratio of the sum of the ages of and twenty years from now to the sum of their ages eight years ago is . If is two years older than and is twice as old as , find the present age of .
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9 2 3 = A + B + C − 2 4 A + B + C + 6 0 ( 1 )
B = 2 + A ( 2 )
C = 2 B ( 3 )
Simplifying ( 1 ) , we get
9 2 3 = A + B + C − 2 4 A + B + C + 6 0
2 3 A + 2 3 B + 2 3 C − 5 5 2 = 9 A + 9 B + 9 C + 5 4 0
1 4 A + 1 4 B + 1 4 C = 1 0 9 2
Substitute ( 2 ) and ( 3 ) into the above equation
1 4 A + 1 4 ( 2 + A ) + 1 4 ( 2 B ) = 1 0 9 2
1 4 A + 1 4 ( 2 + A ) + 1 4 ( 2 ) ( 2 + A ) = 1 0 9 2
1 4 A + 2 8 + 1 4 A + 5 6 + 2 8 A = 1 0 9 2
5 6 A = 1 0 0 8
A = 1 8
It follows that B = 2 0 and C = 4 0