Question 1189297
<br>
There are many ways to set up this problem for solving. The solution from the other tutor is fine, and is  a very typical solution.<br>
I personally would choose a different starting point by looking ahead at the transactions to perhaps make the algebra required for solving the problem a bit easier.<br>
Specifically, since in the first transaction Stephen gives 1/7 of his money to Siew Mei, I would start with<br>
let 7x = amount Stephen starts with
then 540-7x = amount Siew Mei starts with<br>
In the first transaction, Stephen gives 1/7 of his money, x, to Siew Mei.  The amounts the two have are now 6x for Stephen and 540-6x for Siew Mei.<br>
Next Siew Mei gives 1/4 of her money, 135-1.5x, to Stephen.  The amounts they have are now 135+4.5x for Stephen and 405-4.5x for Siew Mei.<br>
The amounts they have now are the same, so they are both half of $540, which is $270.  So we can either solve the equation that says those two expressions are equal; or we can solve an equation that says one of those two expressions is equal to 540/2=270.<br>
{{{135+4.5x=270}}}
{{{4.5x=135}}}
{{{9x=270}}}
{{{x=30}}}<br>
ANSWER: The amount Stephen started with was 7x=$210<br>