Question 290790
Amy = A
Jenny = J <br>
{{{ A = 2J }}}  so {{{ A - 2J = 0 }}} <br>
{{{ A-5 = 3(J-5) }}} <br>
{{{ A-5 = 3J - 15 + 5 }}} <br>
{{{ A-3J = -10 }}} <br>
<br>
Since:
 {{{ A - 2J = 0 }}} <br>
{{{ A-3J = -10 }}} <br>
So -J = -10 therefore J = 10 <br>
Now we've found that Jenny is ten, and since Amy is twice as old:
Jenny = 10,  Amy = 20
and bob's your uncle!