Question 1116104
Chris has two children,Beth and Amy
Beth is 10 years older than Amy
Chris says 'I am twice as old as the sum of Beths age and Amys age
Chris is 40 years old
How old is amy
<pre>Let Amy's age be A
Then Beth's is: A + 10
Chris' is: 2(A + A + 10)
Chris is also 40, so we get: 2(A + A + 10) = 40
2(2A + 10) = 2(20)
2A + 10 = 20
2A = 10
A, or Amy is: {{{highlight_green(matrix(1,4, 10/2, "=", 5, "years-old"))}}}