Question 778957
jacob is three times as old as his brother.
<pre>
J = 3B
</pre>
if jacob's age is 12,
<pre>
12 = 3B
 4 = B,  so the brother is 4
</pre>
how old will jacob be when he is twice as old as his brother?
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Let that be x years from now.  So in x years from now,

Jacob will be 12+x and his brother will be 4+x

12+x = 2(4+x)

12+x = 8+2x

   4 = x

So that will be 4 years from now

So Jacob will be 12+4 or 16 and his brother will be 4+4 or 8.

Answer:  Jacob will be 16.

Edwin</pre>