The ratio of the Mr Koh's money to Mr Sim's money was 7 : 2. <br> Mr Koh gave Mr Sim some money.<br>In the end, Mr Koh had $$\frac{1}{5}$$ as much money as Mr Sim. <hr> If Mr Sim had $100 at first, how much money did Mr Koh give to Mr Sim? <br> <input min="0" type="number" id ="imp6pg092q6_1" class="lineinput" placeholder="?" />