Question 1116321
{{{system(H*S=240,2S=H+4)}}}
<pre>
Solve the 2nd equation for H,  

             H = 2S-4

and substitute in the 1st.

       (2S-4)S = 240

      2Sē - 4S = 240

2Sē - 4S - 240 = 0

 Sē - 2S - 120 = 0

  (S-12)(S+20) = 0

S-12 = 0;  S+20 = 0
   S = 12;    S = -20

Discard negative answer.

Sandy is 12.   (Harry is 20)

Edwin</pre>